Skip to main content

Full text of "Best available pollution control technology - Metal Mining Sector"



STOPPING 

WATER POLLUTION 

AT ITS SOURCE 






MISA 

Munictpal/lndustriol Strategy tor Abatement 



BEST AVAILABLE 
POLLUTION CONTROL TECHNOLOGY 



METAL MINING SECTOR 




Environment 
Environnement 



Ontario 



wp/3763-15Aabo(con,rep/a 



ONTARIO MINISTRY OF THE ENVIRONMENT 
METAL MINING SECTOR 



BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 



DECEMBER 1991 
SECOND EDITION JUNE 1992 



Prepared By: 

KILBORN INC. 

2200 Lake Shore Blvd. West 

Toronto, Ontario 

M8V 1A4 

CANADA 

and 

THE ENVIRONMENTAL APPLICATIONS GROUP LTD. 

20 Eglinton Avenue West, Suite 1006 

Toronto, Ontario 

M4R 1K8 

CANADA 



wp/3763-15/tabotcon.rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

SECTION TABLE OF CONTENTS 

EXECUTIVE SUMMARY 

ACKNOWLEDGEMENTS 

1 INTRODUCTION 

1.1 TERMS OF REFERENCE 

1.2 BACKGROUND 

1.3 METAL MINING SECTOR 

1.4 CONTROL PARAMETERS 

1.5 STUDY FORMAT 

2 DATA SOURCES AND ACQUISITION PROCEDURES 

2.1 DATA SOURCES 

2.2 GEOGRAPHIC FOCUS 

2.3 COMPUTER DATABASE SEARCH 

2.4 PLANT IDENTIFICATION AND SCREENING PROCEDURES 

2.5 ONTARIO PROCESSING PLANTS 

2.6 CANADIAN PROCESSING PLANTS OUTSIDE ONTARIO 

2.7 UNITED STATES PROCESSING PLANTS 

2.8 EUROPEAN PROCESSING PLANTS 

2.9 AUSTRALIAN AND NEW ZEALAND OPERATIONS 

2.10 SITE VISITS 

3 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 

3.1 CYANIDE TREATMENT 

3.2 HEAVY METAL REMOVAL 

3.3 ARSENIC 

3.4 SUSPENDED SOUDS 

3.5 AMMONIA 

3.6 NITRATE/NITRITE 



wp/3763-15Aabotcon.rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE TREATMENT 

SECTION TABLE OF CONTENTS (CONTINUED) 



3.7 


VOLATILE ORGANICS 


3.8 


PHENOUCS 


3.9 


DISSOLVED SOUDS 


3.10 


PH 


3.11 


OIL AND GREASE 


3.12 


TOXICITY 


3.13 


ZERO VOLUME DISCHARGE 



EFFLUENT QUALITY STANDARDS AND REGULATIONS 

4.1 CANADA - FEDERAL REGULATIONS 

4.2 CANADA - PROVINCIAL REGULATIONS 

4.3 UNITED STATES - FEDERAL REGULATIONS 

4.4 EUROPE 

4.5 AUSTRAUA AND NEW ZEALAND 

4.6 OVERALL COMPARISONS 

4.7 QUAUTY ASSURANCE AND QUALITY CONTROL (QA/QC) IN LABORATORY 
TEST WORK 

SCREENING OF WORLD WIDE OPERATIONS 

5.1 ONTARIO PROCESSING PLANTS 

5.2 CANADIAN PROCESSING PLANTS OUTSIDE ONTARIO 

5.3 UNITED STATES PROCESSING PLANTS 

5.4 EUROPEAN PROCESSING PLANTS 

5.5 AUSTRAUAN AND NEW ZEALAND OPERATIONS 

INVENTORY OF SELECTED PLANT OPERATIONS 

6.1 GOLD MINES AND MILLS 

6.2 BASE METAL MINES/MILLS/SMELTERS 

6.3 IRON MINES 

6.4 URANIUM MINES/MILLS 



wp/3763 -15Aat)o'con.rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE TREATMENT 

SECTION TABLE OF CONTENTS (CONTINUED) 

6.5 SILVER MINES/MILLS 

7 PREFERRED (BEST AVAILABLE) TECHNOLOGIES 

7.1 GOLD SECTOR 

7.2 BASE METAL SECTOR 

7.3 IRON ORE SECTOR 

7.4 URANIUM SECTOR 

7.5 SILVER SECTOR 

8 ALTERNATIVE PROCESSES 

8.1 GOLD SECTOR 

8.2 BASE METAL SECTOR 

9 BEST MANAGEMENT PRACTICES 

9.1 PRACTICES EMPLOYED TO MINIMIZE UPSET CONDITIONS 

9.2 PRACTICES TO CONTROL POLLUTANTS AT SOURCE 

9.3 RECYCLE 

9.4 OPERATOR TRAINING AND MANAGEMENT STRATEGIES 

9.5 BACKFILL OPERATIONS 

10 SUMMARY AND CONCLUSIONS 

10.1 APPROACH TO THE SELECTION OF BAT TECHNOLOGIES 

10.2 COMPARISON OF REGULATORY STANDARDS AND APPROACHES 

10.3 PREFERRED BAT LEVEL TECHNOLOGIES 

1 0.4 BEST MANAGEMENT PRACTICES AND ALTERNATIVE TECHNOLOGIES 

10.5 NON-LETHAUTY AND VIRTUAL ELIMINATION OF PERSISTENT TOXIC 
CONTAMINANTS 



wp/37631bAabotcon. rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE TREATMENT 

SECTION TABLE OF CONTENTS (CONTINUED) 

11 REFERENCES AND SELECTED BIBLIOGRAPHY 

11.1 REFERENCES 

11.2 SELECTED BIBUOGRAPHY 

APPENDIX A UST OF CANADIAN MINES, MILLS AND SMELTERS 

APPENDIX B UST OF UNITED STATES MINES. MILLS AND SMELTERS 

APPENDIX C CONTACT LIST - WORLD WIDE OPERATIONS AND AGENCIES OUTSIDE NORTH 
AMERICA 

APPENDIX D GLOSSARY 

APPENDIX E CAPITAL AND OPERATING COST DETAILS FOR BAT 

APPENDIX F CAPITAL AND OPERATING COSTS FOR ZERO VOLUME DISCHARGE 



>A/p/3763-15/acknow1cdqe rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

ACKNOWLEDGMENTS 

The BAT study team wishes to thank operators world wide, who kindly provWed Information for use in 
preparation of the inventory of waste water treatment technology. We are particularly Indebted to 
Boliden Mineral AB of Sweden, to Metaleurop Weser Zink and Norddentsche Affinerie of Germany, and 
to INCO Ltd. and Falconbridge Ltd. of Sudbury. Ontario, for hosting study team visits to their respective 
waste water treatment plants. 

Messrs. John Hawley (Study Director), Zarko Tesic, Gerry LaHaye and Sean Southey of the OMOE; 
Messrs. Leonard Surges and Andrew Wollin of Environmental Canada; Ms. Elizabeth Gardiner and Ms. 
Maxine Wiber representing the Ontario Mining Association; and Messrs. Brian Bell, Bob Michelutti and 
Ron Connell, industry representatives; provided valuable comments during study progress meetings, as 
well as comments on the draft report. 



ACKNOWLEDGEMENTS 



A-1 



wp/3763- 15/sum mary.rep/8 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

EXECUTIVE SUMMARY 

Kilborn Inc. (Kllborn) and The Environmental Applications Group Limited (EAG) were retained by the 
Ontario Ministry of the Environment (OMOE) to undertake a study to identify Best Available pollution 
control Technologies (BAT) applicable to Municipal/Industrial Strategy for Abatement (MISA) Metal 
Mining Sector effluents. BAT has been defined by OMOE as a combination of demonstrated treatment 
technologies and in-plant controls. The Metal Mining Sector comprises gold, base metal, iron, silver and 
uranium operations. 

Specific objectives of the study are: 

1) to provide information on existing, or alternate industrial processes, effluent treatment worl<s 
and processes, chemical substitutions, and employment of water reduction or reuse; 

2) to provide relevant Information on design specifications, as-found treatment performance, 
operating conditions, effluent quality remediation and capital and operating costs of the 
technologies; and 

3) to recommend, where possible, five options for BAT for each section plant or group of 
plants. 

Study efforts were focused on those areas of the world mining community where modern waste water 
treatment practices are known to be employed, and where mining and/or processing operations for ores 
are similar to those used in Ontario. Where treatment technologies were determined to be climate 
dependant, relevance to the Ontario setting was established. Canada, the United States, 
western/northwestern Europe, and Australia/New Zealand were considered to be the relevant 
geographic areas of investigation. 

Data for the study were obtained from: the MISA data base, study team files, published documents, and 
from contacts with a large number of mining, milling and smelting operations. Contacts in this latter 
instance were made through use of a questionnaire and telephone follow-up. In many cases, 
questionnaires were completed from verbal responses. Confidentiality was an issue with some 
operators. Site visits were made to plants in Europe to review technologies different from those 
commonly employed in North America and to selected Ontario plants. 

EXECUTIVE SUMMARY E.S. - 1 



wp/3763-15/surrmary.rcp/a 

Visits to US plants were not made for the simple reason that, with minor exceptions, virtually all gold and 
copper producers operate without surface water discharge, due to their location in net evaporation 
climatic zones. US plants located in such zones generally practise 'zero volume discharge'. Where 
effluent discharge is practised in the United States, principally by lead/zinc producers, treatment 
systems are generally comparable to those used in Canada. 

In addition to a review of operating plants and waste water control technologies, efforts were invested to 
define generic waste water control technologies which are and could potentially be applied to the Metal 
Mining Sector. 

To facilitate evaluation of Interprovincial and international waste water treatment control technologies, a 
comparison of applicable world-wide regulations, guidelines and control practices was made. Standards 
are generally comparable among the areas reviewed with some notable exceptions. Standards for 
cyanide, copper and ammonia are among the more variable ones encountered. 

With minor exceptions, ammonia does not appear to be regulated outside Canada or outside the 
provinces of Ontario, British Columbia and Saskatchewan. Monitoring for toxicity was found to be 
similarly limited outside of Ontario and British Columbia. 

Based on plant operations and performances relative to environmental standards, an inventory of world- 
wide operations was prepared, focusing principally on gold and base metal sub-sectors. Particular note 
was made of the US EPA requirement for 'zero volume discharge' as applied to selected mining/milling 
effluents, together with a description of its relevance to the Ontario settling. 

A principle focus of the US EPA regulations is the elimination (zero volume) of effluent discharge from 
gold, silver, base metal and uranium mines/mills. For base metal and other flotation operations, this 
objective pertains only to plants commissioned subsequent to 1983. Relief from 'zero volume discharge" • 
is provided for facilities located in geographic zones where annual precipitation exceeds annual 
evaporation. In instances where relief from 'zero volume discharge' is permitted, maximum feasible 
recycle is required. 

A review of treatment technologies currently in use within the metal mining and related industries, was 
carried out to identify those technology trains which meet, or could meet, minimum acceptable US EPA 
BAT requirements. Consideration of effluent lethality to fish and to Daphnia magna, and progress 
towards 'virtual elimination' of toxic pollutants were also considered in this review. Based on the review, 

ES - 2 EXECUTIVE SUMMARY 



wp/ J /b:i 1 b/oummory.rep/a 

a set of 'preferred' waste water pollution control technology trains was defined for each of the five sub- 
sectors (gold, base metals, iron, uranium and silver). In defining this set of technologies, the team 
refrained from defining single 'tjesf technologies. Several technology trains which are each capable of 
achieving effluent waste water control standards equivalent to. or better than, those provided by US EPA 
BAT/NSPS (New Sources Performance) standards are defined. Capital and operating costs for each 
technology train were developed for two scales of operation. 

Inclusion of alternative BAT level technologies allows operators the flexibility to address varying site 
conditions, which typify the industry. Most notable in this regard are. varying geological conditions, 
landscape limitations affecting possible methods of tailings disposal, specifics of metal recovery 
processes, and site specific environmental sensitivities. It must be emphasized thtat it is not possible to 
predict the quality of the effluent that would resuit from the application of any BAT option to any 
particular site, without first conducting site specific testworl<. 

BAT level technology trains identified in this report are defined for the gold and base metal sub-sectors 
only. For iron ore processing operations, suspended solids. pH and total iron levels are normally the 
only parameters of concern. These are controlled by primary/secondary settling, with occasional use of 
flocculating agents. 

The greatest diversity of BAT level technology trains, selected herein as preferred technologies, are those 
applying to the gold sub-sector. This is principally because of: (1 ) the complexity of cyanide treatment 
systems, which typically provide combined treatment of suspended solids, cyanide and heavy metals, (2) 
the relatively common association of arsenic (and more rarely antimony) with gold deposits, which 
requires separate treatment from other heavy metals, and (3) the extensive research which has gone into 
the control of gold milling effluents, principally because of the above complexities. 

Waste water control technologies applied to the gold sub-sector in Ontario are as sophisticated and 
varied as any applied throughout the world. The only notable exceptions are the use of chemical 
treatment systems (SO^/Air) for slurries, practised at some operations in Quebec, British Columbia, and 
the United States, and the use of sand filtration for final clarification in New Zealand. 

Thirteen technology trains have been Identified as being capable of achieving BAT level waste water 
control for the gold sub-sector, together with two additional technology trains for treatment of mine 
water alone. Seven of the thirteen technology trains are modifications of the six basic technology trains, 
and are specifically adapted for add-on treatment of arsenic (as well as antimony). Four of the thirteen 

EXECUTIVE SUMMARY E.S. - 3 



wp/3763-15/summary.rep/a 

technology trains are not presently in use, but are instead modifications of teclinoiogy component 
arrangements. 

Five teclinology trains are defined as being applicabie to the base metal mining/milling sector. Two of 
these are standard/universal throughout the mining industry. Two additional technology trains employ 
sulphide precipitation and are in limited use. The most complex of the technology trains is specific to 
stand alone smelter/refineries, and is only known to be used at selected plants in Sweden and Germany. 
Mine water treatment technologies used in the gold sector are also applicable in the base metal and 
other sectors. 

All of the technology trains presented provide progress toward the MISA objective of virtual elimination 
of toxic compounds. Also, subject to confirmation by MISA and other data sources, application of 
preferred BAT options is likely to enable compliance with toxicity requirements in most cases. Non-lethal 
effluents are demonstrated at a number of specific sites. 

Best Management Practices (BMP) are employed throughout the industry in an effort to optimize 
performance, and to minimize environmental impacts. Improving on the efficiency of waste water use 
and recycle, avoiding and providing contingencies for process upsets, optimizing reagent use and 
substituting less toxic reagents where possible, controlling spillage of ammonia based explosives, and 
operator training, are among the more common practices. 



ES - 4 EXECUTIVE SUMMARY 



wp/3763-15Aabotcon.rep/a 



SECTION 1 
INTRODUCTION 



wp/3763- 15/sect1 .f Bp.a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

1 INTRODUCTION 

1.1 TERMS OF REFERENCE 

Kilborn Inc. (Kilborn) and The Environmental Applications Group Limited (BAG) were retained by the 
Ontario Ministry of the Environment (OMOE) to undertal<e a comprehensive study to identify Best 
Available pollution control Technologies (BAT) applicable to Municipal/Industrial Strategy for Abatement 
(MISA) Metal Mining Sector effluents. BAT has been defined by OMOE as a combination of 
demonstrated treatment technologies and in-plant controls. BAT technologies, once defined, are to be 
used as a basis for setting effluent limits for metal mines, mills, and smelters. However, the choice of 
any given technology, or technology train, will be up to the individual operator, so long as the 
regulations are satisfied. 

Accordingly, the objectives of this study are threefold: 

1) to provide infomnation on existing, or alternate industrial processes, effluent treatment works 
and processes, chemical substitutions, and employment of water reduction or re-use; 

2) to provide relevant information on design specifications, as-found treatment performance, 
operating conditions, effluent quality remediation and capital and operating costs of the 
technologies; and 

3) to recommend, where possible, five options for BAT for each sector plant or group of plants. 

As defined by the terms of reference, the study of applicable technologies is to focus on those areas of 
the world which contain mining or processing operations for ores or minerals that are similar to those 
mined in Ontario and where advanced technologies are lil<ely to be used. In addition, where treatment 
technologies are determined to be climate dependent, emphasis is to be placed on operations which 
experience similar climatic conditions to those found in Ontario. 

The process to be employed in the selection of BAT options described herein is to consider the ability of 
a given demonstrated technology to remove contaminants (i.e., cyanide, heavy metals, arsenic, 

INTRODUCTION 1 . i 



wp/3763- 1 5/secn .rep.a 

suspended and dissolved solids, ammonia, nitrate/nitrite, volatile organics, phenolics, oil and grease), as 
well as to control pH In a cost effective and reliable manner. Further consideration is to be given to the 
following secondary goals of potential BAT options: 

non-lethal to fish and Daphnia magna 
maximum use of reduction, reuse and recycling 
smallest transfer of contaminants to other media 
maximum water conservation 
progress towards elimination of contaminants 

The fish species used for toxicity testing in Ontario, according to OMOE protocol, is the Rainbow Trout 
(Oncorhynchus myl<iss). Outside Ontario other fish species may be required for testing, for example In 
the United States the Fathead Minnow (Pimephales promelas) is commonly used. 

For each sector and contaminant of concern, the study is to identify five BAT options (where possible) to 
satisfy the following criteria: 

the BAT that utilizes the best technologies currently in use in North America, Europe, 

Soviet Union. Japan and other countries that are applicable to Metal Mining Sector 

plants; 

a BAT option selected by the US EPA for similar plants; 

a technology train that utilizes the best technologies currently in use in Ontario in the 

Metal Mining Sector; 

at least one technology train that produces an effluent which is non-lethal to rainbow 

trout and/or Daphnia magna. 

at least one technology train consisting of any technology or combination of 

technologies which potentially advance Metal Mining Sector plants towards the long 

range MISA goal of virtual elimination of persistent toxic contaminants. 

From the obtained information a datalaase is to be developed which summarizes technical design, 
operating, performance and cost information for in-plant and effluent treatment technologies. Best 
Management Practices (BMP) including spill prevention and control, to minimize discharges of persistent 
toxic pollutants, are also addressed. 



1 - 2 INTRODUCTION 



v«p/J/63-lb/sect1.rep.a 

The treatment of liquid effluents from uranium plants is addressed in this report, however, consideration 
of the treatment of radionuclide species is specifically excluded since control of these species is the 
mandate of the Atomic Energy Control Board of Canada (AECB). 

1.2 BACKGROUND 

Prior to the initiation of the MISA program In 1986, and promulgation of Ontario Regulation 491/89 
(Effluent Monitoring - Ontario Mineral Industry Sector: Group A), Metal Mining Sector plants monitored 
and reported specific contaminants In accordance with site specific Certificates of Approval. This is still 
the case for Ontario plants. The Province obtained effluent monitoring data prior to MISA through 
OMOE's Industrial Monitoring Information System (IMIS). However, data from several mining operations 
were not included in this data collection due to the focus of IMIS on those plants discharging directly or 
Indirectly to the Great Lakes basin. A number of Metal Mining Sector plants, however, are located in the 
Arctic Watershed. 

Ontario provincial water management guidelines have been summarized in "Water Management: Goals, 
Policies. Objectives and Implementation Procedures of the Ministry of the Environment " and Provincial 
Water Quality Objectives are available for 74 pollutants, but no regulations have been developed for any 
of the priority pollutants Identified in the Ontario Effluent Monitoring Priority Pollutants List (1987) 
(EMPPL). In addition, the OMOE recognized that a limited data base existed conceming the 
concentrations and loadings of contaminants being discharged to Ontario waterways. Metal Mining 
Sector plants generally had little data with respect to the EMPPL. especially for the organic compounds. 
This lack of a comprehensive data base, upon which regulatory limits could be developed, was the 
impetus for implementation of the MISA Effluent Monitoring Regulation (Regulation 491/89). 

The MISA program seeks to strengthen controls on water pollution from all sources. The ultimate goal 
of the MISA program Is the virtual elimination of persistent toxic contaminants for all discharges to 
Ontario's waterways. The method by which this goal is to be attained would be through the imposition 
of pollution abatement requirements on ten major Industrial sectors, municipal sewage treatment plant 
operations and other direct dischargers. The Metal Mining Sector operation is one of the ten major 
industrial sectors. 

The program consists of two sequential phases. In the first phase, sector specific effluent monitoring 
regulations were passed into law (e.g. Ontario Regulation 491/89). These regulations required 
dischargers of wastewater to surface watercourses to monitor point source discharges at regular 
intervals according to specific sampling, analytical, quality assurance and quality control protocols and 

INTRODUCTION 1 - 3 



wp/3753-l5/sect1.rep.a 

procedures. For the Metal Mining Sector plants, the monitoring period was February 1, 1990 to January 
31. 1991. 

The second phase of the MISA program (of which this study is a component) involves the development 
and implementation of Effluent Umit Regulations for ail direct dischargers in all MISA industrial sectors. 
The Effluent Limit Regulations for the Metal Mining Sector will be based, in part, on the capability of the 
BAT options identified in this study. 

1.3 METAL MINING SECTOR 

The Ontario Mineral Industry Sector of MISA includes Metal Mining, Industrial Mineral and Aggregate 
producer operations. Because of the diversity of operations, the Metal Mining Sector is subdivided into 
five distinct categories: base metal (copper, lead, zinc and nickel), gold, silver. Iron, and uranium. In 
total, 67 effluents were monitored during this period. Salt operations were formeriy associated with the 
Metal Mining sector, but were moved to the Industrial Minerals Sector in October 1991. 

The following sections provide a brief oven/lew of each category of the Metal Mining Sector. 
Considerations of effluent treatment relative to the categories are discussed elsewhere in this study 

(Sections 3,6,7). 

Base Metals (copper, lead, nickel, zinc) 

In Ontario, base metals are commonly associated with massive and disseminated sulphide ores, such as 
chalcopyrite, galena, sphalerite and pentlandite. Ore is mined by open pit and underground methods. 
Ore is typically processed by grinding and flotation to produce metal concentrates which are then 
smelted and refined. In some cases, such as with zinc, the smelting process includes roasting, leaching 
and subsequent electrolysis. Common by-products of the zinc smelting/refining process include: 
copper, cadmium, silver, antimony and arsenic. 

Effluents from base metal mills are generally alkaline and may contain elevated levels of copper, lead, 
nickel, and zinc as well as elevated pH. Acid mine drainage is a concern at many mines and mills due 
to the oxidation of sulphide minerals in mine workings, waste rock and tailings. 

Gold 

Gold occurs predominantly as native gold but is also commonly found In association with arsenopyrlte 

and other sulphide minerals. Gold ore is mined by open pit and underground methods. 



1 - 4 INTRODUCTION 



wp/3763- 1 5/Dcct 1 rep.a 

The methods employed In the milling of gold ore Include crushing, grinding, and direct cyanide leaching, 
together with carbon-ln-pulp, carbon-ln-leach, or Merrill-Crowe gold recovery processes. Some plants 
produce a gravity concentrate, prior to cyanide leaching, and more rarely a flotation concentrate is 
produced which may be processed by an outside smelter or leached using cyanide solution. Roasting 
or pressure oxidation may t>e used to liberate gold from refractory sulphide ores. Most plants produce 
gold bullion on-site. 

Gold mill effluents are characteristically alkaline due to the addition of lime, for protective alkalinity in the 
cyanidation circuit. Elevated levels of heavy metals, most notably copper, zinc, and occasionally 
antimony or nickel, are commonly found in gold mill effluents in addition to cyanide and related 
compounds. Where gold Is associated with arsenopyrlte, arsenic is also found in mill effluents. 

Silver 

Silver commonly occurs as native silver, or is associated with sulphide and arsenosulphide minerals of 
cobalt and nickel. Silver is recovered from the ore by gravity separation followed by flotation, where 
necessary. Gravity and flotation concentrates are refined to extract the silver. More rarely, direct 
cyanidation is used. Neariy all of present Canadian production is obtained as a by-product of base 
metal and gold operations. 

Liquid wastes from silver mills are generally alkaline. Arsenic originating from the ores is commonly a 
component of wastewater streams In lioth solid and dissolved forms. 

At present there are no active primary silver mines or mills in Ontario. Primary is defined as the principal 
metal recovered as opposed to one which is recovered as an associated product. 

Iron 

Mineable iron in Ontario occurs in two forms: magnetite and siderite. At present only siderite Is mined in 
Ontario. Iron concentration is accomplished either by magnetic separation and pelletization (magnetite), 
or by heavy media separation and sintering (siderite). Iron plants tend to have a high degree of process 
water recycle. Contaminants are normally restricted to suspended solids, iron and pH level. 

Uranium 

Uranium ore in the Elliot Lake. Ontario area occurs as beds of quartz pebble conglomerate containing 

uranium mineralization in combination with Iron sulphides. All Ontario ore is mined using underground 

methods. 

INTRODUCTION 1 - 5 



vup/ 3?b3 la/sectl rep.a 

Ground ore is treated using sulphuric acid to solubiiize uranium. Tlie uranium is then recovered using 
ion-exchange media and precipitated as a chemicai concentrate with ammonia or nnagnesium. 

Uranium concentrate (yeliowcal<e) Is refined to uranium dioxide and in some cases uranium hexafluorlde 
at Blind River and Port Hope in Ontario, remote from the mine sites. 

Effluents from uranium mills typically contain elevated levels of heavy metals and radionuclide species. 
Radium is the main radionuclide of concern at the operations but is outside the scope of this study. 
Processing plants usually employ lime neutralization of tailings slurry prior to discharge. In one plant 
ammonia is used to produce yellowcake. 

1.4 CONTROL PARAMETERS 

Under the MISA program, the OMOE developed a MISA Monitoring Regulation Database, comprised of 
all data submitted during the monitoring period by the Metal Mining Sector. The OMOE applied various 
statistical methods to the complete monitoring database to provide several statistical reports on the 
unedited data. 

Under the R-15 statistical report for the Metal and Salt Mining Sector (OMOE 1991). a list of parameters 
was identified as per the following procedure. For any given operation, a parameter was assigned 
Priority 1 (for selection of parameters for monitoring and limits) if it was found to be present in 
concentrations above the RMDL (Regulation Method Detection Limit) on greater than 10% of all sampling 
occasions, at a 95% confidence level. Table 1.1 lists the Priority 1 parameters given in the MISA 
Monitoring Data R-15 Report for the Metal Mining Sector, along with the number of effluents, out of a 
total of 67 streams (47 plants), where any given parameter was detected above the RMDL in more than 
10% of all samples (Priority 1). For parameters monitored quarterty (principally organic pollutants) a 
different procedure was used, taking into conskJeration smaller sample sizes. 

The R-15 list generated by the OMOE was used in this study as a preliminary list of candidate control 
parameters, for use in examining the capability of various treatment technologies. A number of 
parameters on the list, principally organics, are listed as occuning in only one effluent. The single 
occurrence of these parameters as R-15 Priority 1 is not related to any processing methods as the 
effluent is derived from a stand-alone mine. More likely, the presence of these parameters is associated 
with the storage and/or use of solvents, oils, greases and similar products at the site. Priority 1 
parameters listed as occurring in only one effluent were therefore eliminated from the group of 
compounds subject to the study of treatment technologies. Emphasis was consequently placed on 

1 - 6 INTRODUCTION 



wp/3763-15/sect1.rep.a 



parameters with occurrence in more than one effluent in examining best available treatment technologies 
and best management practices at metal mines, mills, smelters and refineries. 



Table 1.1 



MISA Monitoring Database of 67 Effluents 
Report R-15 Priority 1 Parameters 



Effluents Where Parameter 
Selected as Priority 1 


Effluents Where Parameter 1 
Selected as Priority 1 | 


Parameter 


Number 


Detection 
Umit mg/L 


Parameter 


Number 


Detection 
Umit mg/L 


dissolved solids 


51 


20 


selenium 


5 


0.005 


Iron 


50 


0.02 


mercury 


3 


0.0001 


ammonia + ammonium 


50 


0.25 


chloroform 




0.0007 


total Kjeldahl nitrogen 


49 


0.5 


benzene 




0.0005 


nitrate + nitrite 


46 


0.25 


toluene 




0.0005 


COD 


44 


10 


chromium 




0.02 


oil and grease 


44 


1 


thallium 




0.03 


sulphates 


44 


5 


vanadium , 




0.03 


total suspended solids 


42 


5 


m-cresol 




0.0034 


chlorides 


41 


2 


p-cresol 




0.0037 


zinc 


41 


0.01 


o-oxylene 




0.0035 


copper 


38 


0.01 


m-xylene 




0.0011 


nickel 


35 


0.02 


p-xylene 




0.0011 


aluminum 


35 


0.03 


2,4,5 trichlorotoluene 




0.00001 


total cyanide 


32 


0.005 


naphthalene 




0.0016 


phenolics (4AAP) 


27 


0.002 


2-methylnaphthalene 




0.0022 


lead 


23 


0.03 


hexachlorobenzene 




0.00001 


pH(outside range 6.5 - 8.5) 


22 


N/A 


pentachlorobenzene 




0.00001 


cobalt 


19 


0.02 


1,2,3 trichlorobenzene 




0.00001 


TOC 


18 


5 


1,2,3,4 tetrachlorobenzene 




0.00001 


free cyanide 


15 




1,2,3,5 tetrachlorobenzene 




0.00001 


arsenic 


13 


0.005 


1,2,4 trichlorobenzene 




0.00001 


uranium 


11 


0.02 


1,2,4,5 tetrachlobenzene 




0.00001 


hexachloroethane 


10 


0.0001 


carbon tetrachloride 




0.0013 


phosphorus 


9 


0.1 


methylene chloride 




0.0013 


1,1 dichloroethane 


7 


0.0008 


trichlorofluoromethane 




0.001 


molybdenum 


7 


0.02 


octachlorostyrene 




0.00001 


antimony 


5 


0.005 


hexachlorobutadiene 


, 


0.00001 








hexachlorocyclopentadlene 




0.00001 



Note: Organic parameters with one occurrence 



INTRODUCTION 



1 -7 



wp/J/tj3-15/-iecI1.rep.a 

1.5 STUDY FORMAT 

The study is presented in a hierarchical order culminating In the selection, description, and costing of 
recommended BAT technologies for pollution control, and best management practices. Sections 1 and 
2 focus on study objectives, background, approach, and data acquisition 

Section 3 provides a brief description of generic technologies potentially available for wastewater 
treatment in the mining industry. Some of the methods described are already in common use within the 
industry. At the other end of the spectrum are technologies which are still in development stages 
(bench scale/pilot plant), and technologies which are used in industries other than mining. The Intent of 
this section is to familiarize the reader with technologies referenced elsewhere in the text, and to 
acquaint the reader with the range of possible technologies. 

Technologies defined in Section 3 are frequently combined, in various sequences, to produce 
technology trains. BAT options are most often technology trains, as opposed to single technologies. 

Section 4 provides a comparison of effluent quality standards applied to the mining industry in the 
geographical areas addressed in this report. Differences in regulatory approaches between Canada, the 
United States, and Europe, are also discussed in this section. 

Sections 5 and 6 focus on data acquisition and contact procedures used to develop an inventory of 
selected plant operations. Recommended/preferred BAT options are selected on the basis of data 
provided in the inventory. 

To the extent that metal mining activities in Ontario focus on gold and base metal operations, most of 
the emphasis in Sections 5 and 6 Is placed on these two sub-sectors. Also, wastewater treatment 
technologies applied to the gold and base metal sub-sectors, essentially cover the possible sets of 
technologies that could be applied to the remaining sub-sectors, i.e., silver, uranium, and iron. This 
excludes considerations related to the treatment and control of radionuclides, which are beyond the 
scope of this study; such contaminants being regulated by Federal authorities. 

Preferred BAT options and technology trains are selected, described, and costed in Section 7. This 
section is the focal point of the entire report. 

Generic technology trains are developed for this section, as opposed to providing descriptions of 'best 
plants' in existence. This approach is more meaningful to general costing and comparisons. For each 

1 - 8 II^RODUCTION 



wp/3763-15/sect1.rcp.a 

BAT trains, capital and operating costs are estimated for two levels of effluent flow. Effluent flows are 
not necessarily related to mine or plant production levels. General assumptions are made regarding the 
size, configuration, and operation of tailings systems, to allow cost comparisons. 

Sections 8 and 9 of the report provide discussions of alternative industrial processes, and best 
management practices, which can be used to further improve effluent quality, reduce the probability of 
upsets, and reduce discharge volumes. 

The range of alternative industrial processes is quite limited. This includes consideration of the possible 
use of alternative reagents. 



INTRODUCTION 1 - 9 



«p/37fi3 15Aabotco 



SECTION 2 
DATA SOURCES AND ACQUISITION PROCEDURES 



wp/3763-15/5ecl2.rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

2 DATA SOURCES AND ACQUISITION PROCEDURES 

2.1 DATA SOURCES 

In order to identify technologies in use in plants throughout the world, the study team employed a 
number of information sources. These sources included: technical databases, the study team's 
knowledge of selected operations, discussions with site personnel and experienced contacts familiar with 
a given site's operations, mining associations, US EPA documentation and, in Ontario, a review of the 
initial reports submitted under the MISA program. The geographic focus and method of data collection 
is described in the following sections. 

2.2 GEOGRAPHIC FOCUS 

The terms of reference for the study specify that the study should focus most closely on those areas of 
the world that mine ore, or process minerals, similar to those in Ontario and where the climate of the 
mining area being investigated is generally similar to that in Ontario. Where climatic differences were 
determined not to be relevant to the application of a given treatment technology, the climatic restriction 
was ignored. Also, in accordance with the requirement of determining applications of suitably advanced 
technologies, efforts were concentrated on those areas known to fiave high environmental and 
technological standards. 

The study team focused the technology search in the following areas: Canada, the United States, 
western/northwestern Europe, Australia and New Zealand. 

South Africa was excluded due to climatic conditions favouring zero volume discharge, even though the 
mining industry is technically advanced and hosted early work on cyanide regeneration. 

Other areas of Africa and South America although having active and developing mining industries, did 
not appear upon initial investigation to be probable sources of BAT level waste treatment technologies 
due to climatic and socio-economic factors. 



DATA SOURCES AND ACQUISITION PROCEDURES 2 - 1 



.~p/3763-15/sect2.rep/a 

2.3 COMPUTER DATABASE SEARCH 

In order to identify available publications and data pertaining to pollution control technologies, a search 
was made to find applicable databases. After a list was developed, the apF)licable databases were 
searched on-line using combinations of key words. Key words such as: wastewater treatment, effluent 
treatment, mining, metals and best available control technology were used to identify publications which 
would apply to wastewater treatment at metal mining sites. Several of the databases searched on-line 
are described below. 

The CAN-OLE system (Canadian On-Une Enquiry System) is the most comprehensive collection of 
Canadian databases. EUAS (Environmental Library Integrated Automated System) and MICROLOG 
(Micromedia Catalogue System) are two of the databases searched through this network. An on-line 
search of the ELIAS database revealed relevant documents of the more than 20 libraries which 
participate in the Environment Canada Departmental Library Network. The MICROLOG database 
provided access to literature and reports from all levels of Canadian government as well as universities, 
research institutions, laboratories, professional societies, corporations, consultants, associations and 
special interest groups. 

Other sources of non-Canadian govemment documents were accessed through CODOC (Co-Operative 
Documents System). NTIS (National Technical Information System). ORD BBS (Office of Research and 
Development Bulletin Board System), and the RREL (Risk Reduction Engineering Laboratory) treatability 
database. CODOC comprises the government document holdings of 1 1 academic libraries in Ontario. 
Publications from Canada, the United States, the United Kingdom, France. Germany and the USSR are 
included in the database. NTIS. the National Technical information Service of the United States, carries 
documents for distribution from over 240 US government agencies. The ORD BBS and the RREL 
Treatability database are two US EPA technical databases. 

In the interest of providing full coverage of pollution control technology employed by the mining industry, 
a diverse selection of technical databases was searched. The Northern Database (Boreal - The Northern 
Database) and the Northern Miner Magazine index provided information on technologies utilized in 
Northern Ontario. Pollution Abstracts and Enviroline cover exclusively environmertt-related literature and 
provided a comprehensive index to over 5000 international publications and references on environmental 
literature. Technology specific to mining was searched on the IMMAGE database through the Institute of 
Mining and Metallurgy in London, England. Other scientific and engineering data bases accessed 
included Scisearch. Current Technology Index, Compendex and CA Search. 



DATA SOURCES AND ACQUISITION PROCEDURES 



wp/3763-15/sect2.r»p/a 

2.4 PLANT IDENTIFICATION AND SCREENING PROCEDURES 

Existing plants were identified through review of the Canadian and American Mines Handbooks, the 
Mining Annual Review (London. 1991). contacts identified by embassies, industrial trade organizations 
and through the study team's mining contacts world-wide. Information regarding plant operations was 
obtained by a number of means including: discussions with plant personnel, questionnaires, the review 
of technical articles pertaining to specific sites and/or given technologies and company files. 

To assist in the collation of Information for the plant sites, the study team developed a questionnaire to 
be completed by site personnel or study team members during discussions with site personnel. The 
questionnaire addressed: plant age/process technology age; milling process and design capacity; raw 
materials; water use/reuse/recyde; flow of wastewater; effluent quality and effluent related regulatory 
requirements. 

The treatment technology at each plant contacted was screened to identify applicable methods of 
wastewater treatment. Where a given mining area has a number of operations with similar technology 
(e.g. natural degradation of cyanide in several northern Ontario gold milling operations), the study team 
selected representative systems based on knowledge of plants and discussions with site personnel. In 
addition, those operations which utilize technologies which are not applicable to Ontario (e.g. net 
evaporation tailings ponds) were eliminated from further consideration. 

2.5 ONTARIO PROCESSING PLANTS 

The study team reviewed initial reports submitted under the MISA program for each direct discharger in 
the Metal Mining Sector. Reviewers completed the questionnaire for each mine site based on the 
information provided in the initial report. Each operation was reviewed with respect to sector group and 
method of effluent treatment. Where several plants operated a similar treatment system, e.g. natural 
degradation, the study team selected representative operations t)ased on: ore characteristics, 
processing methods, overall effluent management practice and effluent performance. 

2.6 CANADIAN PROCESSING PLANTS OUTSIDE ONTARIO 

A list of plants outside Ontario was generated from the 1991 - 1992 Canadian Mines Handbook. For 
those operations where study team members had contacts, questionnaires were completed from 
discussions with plant staff, or from knowledge of the operations. The remaining facilities were 
contacted and requested to complete the questionnaire. In several Instances, questionnaires were 
completed by telephone. All operations were screened In a similar manner to the Ontario plants. 



DATA SOURCES AND ACQUISITION PROCEDURES 2 - 3 



wp/3763-15/secl2.rcp/a 

2.7 UNITED STATES PROCESSING PLANTS 

Operating mines in the United States were identified through the 1990 American Mines Handbool< and 
lists obtained from state agencies. The study team, where possible, used personal contacts to obtain 
data. In remaining cases, the chief environmental coordinator, mill superintendent or equivalent staff 
were contacted and requested to complete the questionnaire. The questionnaire response was then 
followed up, where appropriate, by discussions with plant personnel. In order to gain a better 
understanding of the treatment system's operation and to determine whether a site visit would be 
warranted. Plants relying upon net annual evaporation, deep Injection disposal or agricultural irrigation 
were eliminated from consideration as these technologies are not applicable to the Ontario setting. 

2.8 EUROPEAN PROCESSING PLANTS 

Initial contacts were made with foreign embassies of Sweden. Nonway, Finland, Germany. Belgium. 
France, Italy, Spain and Great Britain in an effort to determine suitable government and industrial 
contacts. Direct contacts were also made with companies known to members of the study team. 
Response from Europe was often slow due to time differences, language difficulties and vacations. 
On the tasis of the early responses received, and a review of the major metal producers in Europe, it 
was determined that the most applicable technologies were those used in Germany and Sweden. 

2.9 AUSTRALIAN AND NEW ZEALAND OPERATIONS 

Contacts with Australian and New Zealand operations were made through previously established 
networks and were limited to specific operations known to be of value to the study. These contacts 
included recent gold mining operations In New Zealand and in Tasmania. 

2.10 SITE VISITS 

Site visits were made to three plants In Sweden and three plants in Germany. Plants of interest in 
Canada were generally well known to the study team members, or to staff of branch offices. In addition, 
there is substantial published information dealing with effluent treatment at various Canadian operations. 
Where data gaps existed, information was obtained by telephone or correspondence. Inco's Sudbury 
complex (Copper Cliff and Nolin waste water treatment plants), Falconbridge's Strathcona plant waste 
water treatment operations, and OMOE's arsenic treatment plant at Deloro, were specifically visited as 
part of this study. 

Initial provision was made for site visits to selected US plants. However, as Information was acquired by 
telephone and written correspondence. It was determined that comparatively few US plants discharged 
effluents to receiving waters. 

2 - 4 DATA SOURCES AND ACQUISITION PROCEDURES 



wp/3763-15/sect2.rep/a 

Where effluent discharge was employed, treatment systems were either similar to those utilized In 
Canada or the host gedoglcal/mlneralogical conditions were not applicat)le to the Ontario setting, e.g. 
the calcareous formations of the Missouri lead be\t 

Two operations in Alaska, Red Dog and Greens Creek were notable exceptions; however, time and 
logistical constraints precluded site visits. Detailed information concerning the effluent treatment system 
employed at both sites was obtained by telephone and correspondence. 



DATA SOURCES AND ACQUISITION PROCEDURES 2 - 5 



vvp/3763-15/labofcon.rep/a 



SECTION 3 
OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

3 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 

Removal technologies for water contaminants identified as primary concern by the MISA program 
(cyanide, heavy metals, arsenic, suspended solids, ammonia, nitrates, organics and dissolved solids) 
that are predominant in mining wastewaters are described in the following sections. The technologies 
are categorized according to the type of contaminant removed and are rated according to their 
utilization in the mining industry as follows: 

widely used - a commonly used method of treatment 

limited use - occasionally used method of treatment 

unique - employed at one or two related sites 

pilot - demonstrated site performance at less than full commercial scale 

potential - a method that could be used but is not, due to economics, 

performance, limited development or present use confined to other 
industries 

Not all of the technologies listed are stand-alone treatments, many are only effective when used in 
combination with other technologies (as a "technology train") 

The utilization of the technologies in the removal of contaminants listed in Sections 3.1 to 3.11 is shown 
in Table 3-1. Potential technologies are not included in this table. 

3.1 CYANIDE TREATMENT 
Widely Used 

• natural degradation 
. INCO SQî-Air 

hydrogen peroxide 
Limited Use 

alkaline chlorination 

acidification - volatilization - regeneration (AVR) 

engineered wetlands 

Hemlo Gold process 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 1 



v«D/3763-15/sect3.rep/a 

Unique Use 

Homestake bio-degradation process 
Pilot 

Vitrol<ele™ 

MNR Degussa process 

ion exchange (in combination with AVR) 
Potential 



electrolytic decomposition 

ozonation 

activated carbon 

Noranda SO^ process 

Kastone' peroxide process 

CELEC process 

ferrous sulphide adsorption 

Wastewater treatment technologies described In this section include not only cyanide 
treatment/destruction, but also in many cases the concurrent and/or sequential removal of heavy metals 

as well. 

Widely Used 

Natural Degradation 

Natural degradation involves the removal of cyanide and associated cyanide-metal complexes from 
wastewaters by naturally occurring processes while the wastewaters are retained for extended periods in 
holding ponds, usually tailings ponds. The degradation of cyanide and metal-cyanide complexes results 
from a combination of physical, chemical and biological processes including volatilization, chemical and 
photochemical decomposition , chemical and microbial oxidation, precipitation of metals, hydrolysis, and 
adsorption on to solids. 

Natural degradation is influenced by a number of variables including cyanide species and their 
concentrations In solution, pH, temperature, sunlight (UV), aeration, pond conditions (area, depth, 
turbidity, turbulence, ice cover, retention time) and the presence of bacteria. During the removal of 
cyanide, and following decomposition of the metal-cyanide complexes, metals are removed concurrently 
as precipitates, generally as hydroxides, but sometimes as insoluble metal-cyanide complexes, and as 
adsorbed cations on suspended solids which subsequently settle. Ammonia is a product of cyanide 
oxidation promoted by both natural degradation and chemical treatment. The extended retention times 

3 - 2 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wpA3/63-1b/sect3.rep/a 

provided by well-engineered, natural degradation systems encourages dissipation and volatilization of 
the ammonia. 

principal advantages/disadvantages 

• effluent aging ponds can readily be constructed and/or developed in conjunction witli 
tailings solids storage facilities 

• extended retention times and exposure to atmosphere and sunlight, promotes the 
degradation and/or removal of a large number of contaminants other than Just cyanide 
(for example ammonia) 

• severe climates restrict effective use in Canada to non-winter periods, normally requiring 
extended holding capacity and batch discharges, unless used in conjunction with other 
treatment methods. 

INCO sa -Air 

This is a process developed and patented by Inco in which the cyanide ion and the cyanide component 
of base metal cyanide complexes are selectively oxidized to cyanate by a mixture of SOj and air, in the 
presence of copper as a catalyst, in a controlled pH range. Iron, present as ferrocyanide, is not oxidized 
by the process, but is precipitated as a complex with the copper and zinc released from the cyanide 
complexes. Sulphur dioxide can be added as a gas, as sulphurous acid, or as a solution of sodium 
sulphite or sodium metabisulphite. The process has been applied to the treatment of both slurry and 
solution waste streams. 

principal advantages/disadvantages 

• proven effective at a number of operations 

. effectiveness easily controlled by variable reagent addition in response to varying 
effluent composition 

• suitable for treatment of both clear solutions and slurries 
. handling and safety precautions with SO^ gas and liquid 

Hvdrooen Peroxide 

This process is similar to the SOj-Air process in that free and metal-complexed cyanide, except for iron 
cyanide, is oxidized to cyanate. often in the presence of copper as a catalyst and In a controlled pH 
range. The base metals copper, nickel and zinc, freed by oxidation of cyanide, form hydroxide 
precipitates. Ferrocyanide is precipitated by copper or zinc. Any excess hydrogen peroxide (H202) 
decomposes to water and oxygen. Hydrogen peroxide is added directly as a liquid normally at 
concentrations of 50 - 70% by weight. The process has been applied to both slun7 and solution 
streams but appears to be more effective in clear solutions than in slurry. 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 3 



WP/376J 1b/serl3.rep/a 

principal advantages/disadvantages 

proven effective at a number of operations 

• effectiveness easily controlled by variable reagent addition in response to varying 
effluent composition 

• not as yet demonstrated to be effective for tfie treatment of slurries 

• fiandling and safety precautions with H2O2 

Limited Use 

Alkaline Chlorination 

Alkaline chlorination is a chemical treatment method tfiat destroys cyanide (and cyanide complexes of 
copper, zinc and nickel) by rapid oxidation with hypochlorite ions at pH values In the range of 10 to 11. 
The hypochlorite is provided by the reaction of chlorine gas with water or as sodium or calcium 
hypochlorite. The metals precipitate as hydroxides as the complexes are broken down. As far as the 
mining industry is concerned, this process has fallen into disuse since the emergence of the Inco SO^- 
Air, hydrogen peroxide and Hemlo processes. It is still widely used in the metal finishing and plating 
industry and occasionally in gold mining areas outside Canada where partial treatment Is acceptable. 
principal advantages/disadvantages 

• costly and complex installation 

• safety considerations related to chlorine gas handling 

• primarily effective on free cyanide only, and where high concentrations of cyanide are 
present 



Acidification - Volatilization - Regeneration (AVR) 

This process is based on the volatility of hydrogen cyanide resulting when cyanide slurry or solution Is 
acidified This acidified slurry/solution is then passed counter-current to a stream of air in a series of 
packed towers. The solution, stripped of hydrogen cyanide, is reneutralized with lime, and directed to 
waste. The effluent air stream containing the elevated hydrogen cyanide is directed upflow through a 
second series of packed columns counter-current to a lime or sodium hydroxide solution to produce 
regenerated cyanide solution for recycle. This process is effective for removing free cyanide, but is not 
effective (in itself) for removing metal-complexed cyanide. Also, scaling and other problems have been 
encountered such that its success to date has been mixed. 

CANMET has proposed an AVR process for the treatment of barren solutions from Merrill-Crowe 
operations. The entire barren stream is acidified to pH 2 to 3 with sulphuric acid. The precipitate is 

3 - 4 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-1b/sect3.rep/a 

recovered by filtration. The bulk of the filtrate Is reneutralized with lime to reverse the HCN/CN 
equilibrium and then recycled to the leach stage. This recycle solution has a low metallo-cyanide 
content and contains all of the cyanide produced in the acidification step. A small bleed stream of the 
filtrate (typically less thian 10%) is treated by aeration-volatilization prior to reneutralization to pH 9.5. 
The volatilized HCN is recovered by absorption in the stream which is recycled to the leach. This 
process has been described by McNamara (1989). 
principal advantages/disadvantages 

• costly and complex installation 

• safety considerations related to HCN gas handling 

• primarily effective on free cyanide only, and where high concentrations of cyanide are 
present 

• cyanide recovered 

Engineered Wetlands 

Plant materials can uptake heavy metals through their Incorporation into tissue structures, and through 
surface adsorption. Metal removal is most effective during the growing period. Wetlands and 
particularly muskeg, also provide an effective filter for entraining suspended solids. 

The demarcation between engineered and naturally occurring wetlands is not always distinct. 
Frequently, natural wetlands are modified, using engineered structures (dykes, berms), to either enhance 
plant growth, or to manage flows; for example, Asarco's Sweetwater lead/zinc operation in Missouri and 
Canamax's gold mine (currently shut-down) In Northern Ontario. 

In northern climates, wetlands are most effective during the non-winter period. For operations in 
Northern Ontario where large tracks of muskeg are present, there is significant potential to modify these 
wetlands, to maximize efficiency. Two gold mills in northern Saskatchewan (Jolu and Gemini Gold) use 
this approach (refer to Table 6-1, Section 6). 
principal advantages/disadvantages 

• most effective when used to modify and/or improve existing wetlands 

• musky areas suitable for modification, wetlands in southern Ontario often provide critical 
habitats for wildlife and rare plants (e.g. orchids) 

• long-term implications of heavy metal accumulation relative to hazardous waste 
regulations (Regulation 309) need to be considered 

• requires large land area 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 5 



«P/3763-15/5ecI3.rep/a 

Hemlo Gold Process 

This is a patented process (Noranda Inc.) involving the addition of a premixed solution of copper 
sulphate and fen-ous sulphate (CuSQj/FeSOl,) to mill solution originating from the grinding circuit 
thickener and after recovery of contained gold by activated carbon in columns. The process has been 
developed during several years of operation to the system now in use (1991) and described here. The 
mill tailings slurry is discharged to a large tailings containment/pond area, where natural degradation 
takes place. During the non-winter period, aged effluent from the tailings pond is reclaimed to the mill 
for use as grinding water. The resulting slurry is directed to the thickener, with the thickener underflow 
passing to the leach circuit. The (clarified) thickener overflow flows to the carbon columns, and from 
there to the wastewater treatment system. A significant portion of the heavy metals contained in the 
reclaimed tailings effluent is removed from the solution during the grinding process, reducing the amount 
of subsequent treatment required. 

The premixed CuS04/FeS04 reagent, added to the mill solution in which the pH is controlled at 
approximately 9.5, oxidizes ferrous ions to form ferric hydroxide, while cupric ions are simultaneously 
reduced to cuprous ions. The resulting cuprous ion removes free cyanide when required as an insoluble 
cuprous cyanide precipitate. Removing free cyanide subsequently results in the dissociation of copper, 
nickel and zinc cyanide complexes, leading to further removal of cyanide by cuprous ions. Copper, 
nickel, zinc, antimony and molybdenum are co-precipitated from solution with ferric sulphate addition 
and a solution pH of approximately 4.5. Lime is then added to increase the solution pH to 7.0 and 
hydrogen peroxide is added as required to remove residual cyanide. A reactor clarifier is employed to 
recover precipitate as sludge, which is pumped together with the mill tailings slurry to the tailings pond. 
Final effluent is discharged to the environment, 
principal advantages/disadvantages 

• used in conjunction with natural degradation and extensive reclaim to grinding - which 
produce low strength cyanide solutions 

• effective for removal of arsenic, antimony and molybdenum 

• requires a carbon handling/stripping system 

• only two demonstrated plants 

Unique Use 

Homestake Bio-Deoradation Process 

This operation employs mechanized biological removal of cyanide and thiocyanate from a blend of mine 
water and tailings pond decant. Treatment involves two steps. Cyanide and thiocyanate (SCNT) are 
converted in the first step to cartxsn dioxide and ammonia by microorganisms acclimatized to increasing 

3 - 6 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/J/63-15/sect3.iep/a 

cyanide and thiocyanate levels, while sulphur Is oxidized to sulphate. The second step involves 
nitrification whereby ammonia is converted first to nitrite and then to nitrate by bacteria that grow 
spontaneously in the presence of ammonia. Metals, including some ferrocyanide. are absorbed by the 
bacteria. Flocculated sludge is subsequently removed in ciarifiers and filters, and disposed of in the 
tailings area. Temperature and feed concentrations vital to the organisms are quite critical and rt is 
uncertain whether the process could be successfully employed in Canada. 
principal advantages/disadvantages 

• used only at one operation - South Dakota 

• temperature sensitive 

• only demonstrated on dilute solutions 

• principal advantage is the conversion of ammonia to nitrate and nitrite 

• high capital and operating costs 

Pilot 

Vitrokele^"^ 

The origin of this technology dates back to the early 1980's to research in the medical faculty at McGill 
University in Canada. This research was concerned with the efficient ways that living cells captured 
trace metals essential for life. As research progressed It became evident that some of the special 
molecules used by biological systems to capture metals could be synthesized and used to recover 
metals from solution. 

The technology was first commercialized to recover toxic metals from plating wastes. Compositions with 
the active chelating groups were applied on vitreous grains as the substrate. Hence the name Vitrokele. 

The world wide rights to the technology are held by Jasmetech who are also responsible for its 
marketing. 

The process today employs a mixed function adsorbent which is capable of reversibly binding a range of 
metal cyanide complexes. The adsorbent contains ligand functional groups on a highly cross-linked 
polystyrene bead. 

The adsorbent, after contact with the process stream in a series of contactors (similar to a CI P process) 
is loaded with cyanide and metallocyanide complexes. This loaded adsorbent is removed and washed 
before metal elution using zinc tetracyanide. Cyanide is then eluted using sulphuric acid. The eluted 
resin is washed before recycle to the adsorption circuit. 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 7 



v.p/3 763-1 5/secI3.rep/a 

The metal eluate is acidified with sulphuric acid to convert dissolved zinc (but not copper) to the cationic 
form before recovery on a cation exchange resin. The zinc free eluate is then treated with a sulphide or 
hydrosuiphide to precipitate copper as a sulphide. The copper sulphide is removed by filtering and the 
filtrate is combined with the acid eluate from the cyanide elution before neutralization to reverse the 
HCN/CM equilibrium. The recovered cyanide Is recycled to the leach stage. 

The loaded cation exchange resin is eluted with NaCN to regenerate zinc tetracyanide which Is recycled 

to metal elution. 

The process chemistry has been tested on a laboratory scale and the total process has been piloted at 
Gabanlntha and Cosmo Howley Mines in Australia and at Hope Brook and Bell Creek Mines in Canada. 

Vitrokele technology is claimed to have the best potential for the virtually complete removal and efficient 
recovery of cyanide, dissolved base metals and precious metals from gold plant tailings in slurry or 

solution form. 

The design, construction management and commissioning of Vitrokele projects in the mining sector will 
be carried out by the Signet Engineering Group. 

This process is generating interest as a possible viable alternative to some of the more conventional 
processes described above. The suppliers claim that the resin can be regenerated efficiently and that it 
has a high resistance to both chemical fouling and physical attrition. Results available from several pilot 
tests have not yet demonstrated the long term efficiency of the process and the resistance of the resin 
to attrition and fouling. 

principal advantages/disadvantages 

• claimed to have the best potential for the complete removal and recovery of cyanide, 
dissolved base and precious metals from gold tailings 

• effective for treatment of clear solutions and slurries 

• long-term performance/regeneration characteristics of resin remains to be proven 

• high capital and operating costs (potential savings on cyanide use and metal recovery) 



3 - 8 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



vvp/3;63 15/scct3.rcp/0 

"MNR" (Dequssa) Process 

This process is particularly suited to the treatment of cyanide iiquors containing a high concentration of 
weak acid dissociable (WAD) cyanide complexes. These solutions arise in the cyanidation of certain 
sulphides and oxide ores of copper such as chalcocite. malachite and azurite. 

The precious metals are recovered from the clarified solution by conventional means (e.g. activated 
carbon, Merrill-Crowe). The solution is then acidified with sulphuric acid followed by the addition of a 
sulphide or hydrosulphide to precipitate the copper. The copper sulphide or hydrosulphide Is recovered 
by filtration. The pH of the filtrate is then raised to reverse the HCN/Cl^f equilibrium before this solution 
Is recycled to the cyanidation process. The patent for the process is held by Degussa A.G. The major 
difference between this and other AVR based processes is that no HCN desorption/adsorption step is 
required. 

Laboratory and semi-pilot plant tests have been carried out in U.S.A., Germany and Australia since 1984. 
laboratory trials are currently in progress for possible application of this technology at East Malartic 
Mines in Quebec. 

principal advantages/disadvantages 

• permits recovery and re-use of cyanide 

• only applicable to use with barren (high strength cyanide) solutions 

• metal sulphide precipitates require disposal in an oxygen free environment, or shipped 
to smelter 

• free HCN under pressure pores potential safety concerns 

Ion Exchange in Combination with AVR 

Dissolved metallocyanide complexes are readily absorbed from slurries and solutions by both strong and 
weak base anion - exchange resins. The loaded resins are subsequently eluted and the relatively small 
volume of concentrated eluate is subjected to AVR for recovery of the cyanide. 

Different versions of this process have been proposed by, for example, CANMET. In this process the 
loaded resin is eluted using acid. The liberated cyanide is stripped by air and absorbed in a solution of 
sodium hydroxide for recycle to leaching. The metals in the acid eluate are recovered using a cation 
exchange resin and ultimately precipitated as hydroxides. 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 9 



wp/J763-lb/sect3.rep/8 

principal advantages/disadvantages 

• high capital and operating costs 

safety considerations related to HCN gas handling 

• cyanide recovered for reuse 

Potential 

Electrolytic Decomposition 

This technique subjects cyanide wastewaters to anodic electrolysis at high temperatures. The cyanide Is 
subsequently broi<en down to the gaseous products: carbon dioxide, nitrogen and ammonia, with 
cyanate as an intermediate product. The process continues until the waste electrolyte loses its capacity 
to conduct electricity, signalling the end of the reactions. The oxidation rate and efficiency can be 
enhanced at low concentrations by the addition of sodium chloride to the cyanide solution. 
principal advantages/disadvantages 

• limited to use with barren (high strength) solutions 

Ozonation 

This process produces similar results to that of alkaline chlorlnation process, but its potential for full 
scale use is somewhat limited. Cyanide complexes (with zinc, nickel and copper) are destroyed as 
cyanide and thiocyanate are both oxidized very rapidly to cyanate in the presence of ozone at a pH of 9 
to 12. The reactions are almost Instantaneous in the presence of traces of copper ions which act as a 
catalyst in solution The additional use of ultraviolet (UV) light in combination with ozone can reduce 
complex iron cyanides which are more resistant to ozone treatment. 
principal advantages/disadvantages 

. high estimated capital and operating costs - particularly for power consumption 
associated with required on-site ozone generation 

Activated Carbon 

This process removes cyanide from wastewaters using granular activated carbon. Cyanide is first 
adsorbed by the activated carbon, and then catalytically oxidized. The presence of cupric ions, which 
results in the formation of copper cyanides, enhances the adsorption capacity of the carbon. The 
continuous addition of copper causes hydrolysis of cyanate, yielding ammonia and carbon dioxide. The 
bed must be periodically regenerated and would have the disadvantage of increasing the copper load of 
the waste. 

principal advantages/disadvantages 
not a selective process 

3-10 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



• expected high capital and operating costs associated with carbon stripping, and iikeiy 
inefficiencies in the removal of some cyanide species 

• greatest potential where an existing carbon stripping system in place 

Noranda SO, Process 

This is a patented process employing pure SC^ and copper (as a catalyst) for the destruction of cyanide. 
The Injection of air as an oxidizer is not required. Full scale testing has been completed using tailings 
pond supernatant at Noranda's Golden Giant mine near Hemlo, Ontario, with considerable success with 
cyanide, copper and iron removals greater than 99%. Subsequent treatment methods have nevertheless 
been developed for use at the Golden Giant Mine (see Hemlo Gold Process, above). 
principal advantages/disadvantages 

• comparative efficiency relative to the INCO SC^-Air process remains to be determined 

• use at the pilot plant location was abandoned in favour of the Hemlo Gold Process 

Kastone" Peroxide Process 

A specially stabilized 41% hydrogen peroxide solution (Kastone*) in the presence of formaldehyde and 
copper is utilized to treat cyanide wastes. The oxidation products are cyanate, ammonia and various 
organic acids. Thiocyanate is not oxidized. The process has been tested at pilot plant scale. Chemical 
requirements were claimed to have been excessive although detailed data have not been reported. 
principal advantages/disadvantages 

• reported high reagent costs 

• comparative efficiency relative to the more conventional hydrogen peroxide treatment 
process remains to be determined 

CELEC Cyanide Regeneration System 

The CELEC system has been developed to treat clear solutions containing cyanide complexed with 
copper or as thiocyanate. A two-part electrolytic cell is used to : (a) recover metallic copper and 
residual precious metals by plating on carbon electrodes and to produce free cyanide, (b) to recover 
metal by stripping the electrodes and plating as a sheet. The cyanide remaining in solution is suitable 
for reuse, without the need of AVR regeneration/recovery process. 
principal advantages/disadvantages 

• appropriate only for clear solutions carrying high concentrations of metals and/or 
cyanide 

• potential revenue from metal sale and cyanide regeneration 

• high operating cost 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3-11 



wrj/3763-lb/sccl3.rep/a 

Ferrous Sulphide Adsorption 

Tliis process patented by Cominco Is based on the adsorption of cyanide and metallocyanides on 
freshly prepared particles of ferrous sulphide. The process has generated little Interest Ijecause It does 
not produce an effluent of a quality acceptable for discharge to receiving waters. 
principal advantages/disadvantages 

• does not appear to produce an effluent of sufficient quality to allow discharge 

3.2 HEAVY METAL REMOVAL 
Widely Used 

tailings pond 
settling ponds 
hydroxide precipitation 

- lime precipitation 

- sodium hydroxide 
■ limestone 

Limited Use 

mechanical settling 

coagulants/flocculants in combination with precipitating agents 

sulphide precipitation 

mechanical filtration 

passive filtration (including exflltratlon) 

engineered wetlands 

ion-exchange 
Potential 



carbonate precipitation 

reverse osmosis 

electrodialysis 

ultra-filtration 

activated carbon adsorption 

electrowinning 

cementation 

silicate precipitation 

Bio-fix process 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-15/secl3.rcp/a , 

Wastewater treatment processes described here, for heavy metal removal, are viewed primarily from the 
perspective of treating solutions and/or slurries which do not contain significant concentrations of 
cyanide. Where such concentrations are present (i.e. greater than about 1-3 mg/L) reference should be 
made to Section 3.1. 

Widely Used 

Tailings Pond 

Tailings ponds provide containment for the deposition of mill slurry solids, and heavy metals that have 
precipitated out of solution as hydroxides and other solids. The rate of heavy metal removal and 
subsequent deposition will depend on: tailings pond physical characteristics, pH/alkalinity values, grind 
characteristics, the potential for acid mine drainage. Under favourable circumstances, tailings pond(s) 
alone may provide sufficient treatment to allow discharge to the environment. This is particularly true 
when t)ase metals are associated with carbonate formations which produce natural all<aline waters (such 
as the Missouri lead belt in the U.S.). Otherwise, tailings ponds comprise an integral component of 
virtually all other treatment systems, save those for just mine water or acid mine drainage. 
principal advantages/disadvantages 

• effluent aging ponds can readily be constructed and/or developed in conjunction with 
tailings solids storage facilities, such facilities being almost universal throughout the 
industry 

. extended retention times also facilitate the removal of other compounds, such as 
ammonia and cyanide species, which can complex heavy metals 

• typically high capital and low operating costs 

Settling Ponds 

Suspended solids in the form of fine tailings, as rock and as residual precipitates are generally removed 
by gravity in a settling pond. Settling ponds are frequently found in a series arrangement Into which 
treated tailings water and mine water are discharged prior to recycle or final discharge to the 
environment. These ponds differ from tailings ponds primarily in size and in concentrations of influent 
solids. The size of the settling pond required for satisfactory removal of suspended solids relies on such 
parameters as particle size, pH and temperature of the water, wind and wave effects, depth of water, 
and inlet and outlet configurations. 

principal advantages/disadvantages 

• universally used through the industry for removal of suspended solids from mine water, 
for secondary settling of tailings pond effluent, and for the settling of sludges produced 
by waste water treatment plants 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3-13 



■n^l/J/b^ 15/secl3.rcp/a 

• comparatively low cost and simple maintenance 

• very effective for most requirements provided that proper design considerations are 
tal<en into account 

often used in conjunction with other treatments and treatment aids 

Hydroxide Precipitation 

Chemical precipitation of hydroxides is obtained by the addition of an alkali to the waste stream to 
produce metal hydroxide precipitates. This process enhances metal deposition due to the elevated pH 
level and the availability of hydroxide Ions required for metal precipitation and is universally used 
throughout the mining industry. For maximum effectiveness, the process usually requires that metal ions 
in the waste stream are free, uncomplexed Ions, and that the pH is adequately high to insure optimum 
precipitation. Lime in its various forms and/or limestone (for extreme acid conditions) are the most 
common compounds employed. Sodium hydroxide (NaOH) is occasionally used in place of lime to 
precipitate metal hydroxides, especially where flows are small and stronger pH adjustments are required 
or formation of gypsum scale could be a problem or increase operating costs, 
principal advantages/disadvantages 

• lime is effective, economical and easy to handle 

sodium hydroxide is used more within the milling circuit wherever a stronger base is 
required and where scaling Is to be avoided 

• for waste water treatment, sodium hydroxide use is primarily restricted to the treatment 
of some smelter effluents 

• limestone has limited capacity to increase pH. and is also prone to surface scaling, 
which restricts further reactivity 

Limited Use 

Mechanical Settling 

The equipment type is selected based on the flow range of effluent, the type of precipitate to be handled 
and the desired overflow (treated solution) clarity. Tanks are typically of concrete or metal and a 
rotating rake mechanism moves settled sludge from the bottom to a central discharge point. The 
performance of this equipment is frequently enhanced by the addition of coagulants and/or flocculants. 

Available types of equipment include thickeners, simple clarifiers, reactor/darifiers, high rate type 
clarifiers, plate type (Lamella) clarifiers. 



3-14 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-15/sect3.rép/a , 

Sludge produced by mechanical settling devices Is frequently dewatered to improve handling 
characteristics or cost using various types of mechanical filtration equipment. The alternative is storage 
in a pond or lagoon where evaporation may assist In moisture reduction. 
principal advantages/disadvantages 

• effective for the removal of finely suspended and colloidal material when used In 
combination with coagulating/flocculating agents 

choice between enhanced affluent retention in tailings ponds and secondary settling 
ponds, versus use of mechanical settling is determined by the nature of contaminants in 
the effluents, comparative efficiencies of contaminant removal, and costs 

• high capital and operating costs 

• sludge disposal required 

• where acid mine drainage is being treated, mechanical clarification, with sludge return, is 
the treatment of choice In order to produce a sufficiently thickened sludge to allow 
proper settling and storage 

Coaqulants/Roccuiants in Combination with Precipitating Agents 

Coagulants reduce electrostatic surface charges to facilitate settling and flocculation, which is the 
physical process of aggregating solids into larger particles. The resulting precipitates, from the various 
chemical additions described above, can be removed with the aid of a flocculating agent and/or 
coagulant, assisted by settling, mechanical clarification or filtration. 
principal advantages/disadvantages 

• research and experience with practical applications has led to the development of a 
large array of coagulating and flocculation agents - providing the industry with an 
inventory of products to meet almost any need 

• coagulants and flocculants are universally used in combination with mecfianicai 
thickening and clarification (reactor/clarlfiers) 

• can be a significant operating cost 

Sulphide Precipitation 

Sulphide precipitation can theoretically achieve lower dissolved metal levels than those achievable by 
hydroxide precipitation due to lower solubilities of metal sulphides compared with metal hydroxides. 
See Figure 3.2.1 for relative solubilities of hydroxides and sulphides. Sulphide can be added typically as 
sodium sulphide, but eilso as ferrous sulphide in alkaline conditions to assure generation of sulphide ions 
rather than bisulphide or hydrogen sulphide gas. The precipitates can then be removed by filtration or 
by mechanical clarification. Also, while sulphide sludges are essentially insoluble, sulphides are readily 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3-15 



wp/J?63-1S/sect3.rep/a 

oxidized to sulphates which are highly soluble. For this reason, sludge disposal in an oxygen free 
environment, such as a suitable landfill, within tailings systems, or as bacl<fill is normally required. 

The use of sulphide precipitation is especially suited to the treatment of high strength (elevated metals) 
smelter/refinery wastewaters, as noted during site visits to plants in (West) Germany and Sweden. The 
precipitate In many cases can be recycled to the smelting process to eliminate disposal systems. 
Sulphide precipitation is also employed at certain minesites where particularly low levels of specific 
contaminants must be attained and/or where precipitation at low pH levels is desirable. Sulphide 
precipitation is an element of several cyanide removal technologies discussed in Section 3.1. 
principal advantages/disadvantages 

• metal sulphide solubilities are lower than those of either metal hydroxides or metal 
carbonates 

. metal sulphides precipitation is most effective in the pH range 4-5 (using sodium 

sulphide), which would require pre and post-neutralization adjustment for most effluents 

• disposal of sulphide precipitates requires an oxygen free environment to prevent 
oxidation to readily soluble sulphates 

Mechanical Filtration 

Sand filters, and in (West) Germany styrofoam bead filters, are used as a final polishing step, at some 
operations, to remove residual precipitated/flocculated heavy metal hydroxides and sulphides. In 
Canada, the only operation using sand filters appears to be Minnova's Samatosum Division (open pit 
copper-lead-zinc producer) in British Columbia. Sand filters are also used in New Zealand and at 
several plants in Sweden. Arrangements are not different from those used for other wastewater 
treatment, including provision for backwashing. 

Dewatering of precipitate sludges produced by mechanical settling is frequently conducted by 
mechanical filters designed to maximize liquid removal. Typical units are plate and frame pressure 
filters, belt filters and tube filters. 

principal advantages/disadvantages 

• application of this common waste water treatment technology to mining effluents is 
comparatively recent - normally in response to stringent site specific environmental 
standards 

• effective as an add-on treatment step for removal of heavy metals following settling 
and/or mechanical clarification 

• provision for backwashing allows for rejuvenation of the filter bed 

3-16 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-15/sec13.rep/a 

• more expensive than conventional systems, such as settling, with higher operating costs 
sludge handling must be considered 

Passive Filtration 

Exfiltration is a type of passive filtration process whereby wastewaters contained In settling or tailings 
ponds seep through earthen dams or soils lining the bottom and sides of the pond and which act as a 
filtering mechanism. As the water seeps through, suspended solids are retained. This mechanism is 
effective during the initial use of the pond, but gradually becomes less effective as the soils become 
clogged, allowing little or no further seepage. Effluent control and monitoring is also sometimes difficult. 
principal advantages/disadvantages 

limited use as an engineered treatment system 

• plugging/fouling of the filtration 2one (typically sand) may require periodic removal and 
replacement of portions of the filtration bed - in the absence of backwashing capabilities 

• exfiltration through the floor of tailings and settling ponds would be a temporary 
phenomenon becoming increasingly restricted by the deposition of fine solids - 
dependent upon favourable (coarse substitute) overburden and water table 
characteristics. 

Engineered Wetlands 

Plant materials can uptake heavy metals through their incorporation into tissue structures, and through 
surface adsorption. Metal removal is most effective during the growing period. Wetlands and 
particularly muskeg, also provide an effective filter for entraining suspended solids. 

The demarcation between engineered and naturally occurring wetlands is not always distinct. 
Frequently, wetlands are modified, using engineered structures (dykes, berms), to either enhance plant 
growth, or to manage flows; for example, Asarco's Sweetwater lead /zinc operation in f\4issourl and 
Canamax's gold mine (currently shut-down) in Northern Ontario. 

In Northern climates, wetlands are most effective during the non-winter period. For operations in 
Northern Ontario where large tracts of muskeg are present, there is significant potential to modify these 
wetlands, to maximize efficiency. Two gold mills in northern Saskatchewan (Jolu and Gemini Gold) use 
this approach (refer to Table 6-1, Section 6). 
principal advantages/disadvantages 

• most effective when used to modify and/or improve existing wetlands 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3-17 



i^p/3763-15/secl3.rep/a 

• musky areas suitable for modification, wetlands in southern Ontario often provide critical 
habitats for wildlife and rare plants (e.g. orchids) 

• long-term implications of heavy metal accumulation relative to hazardous waste 
regulations (Regulation 309) need to be considered 

• requires large land area 

Ion-Exchange 

Ion exchange normally occurs in a column filled with polymeric beads which have a chemicîU affinity for 
metallic anions (including metal cyanide complexes). The anions are extracted from wastewater as rinse 
waters are passed through the column bed. Flow through the column must be periodically stopped to 
allow regeneration of the bed. This regeneration is conducted before the "breakthrough" point when the 
resin bed has reached its maximum capacity for metal ion adsorption. Regeneration is performed by 
passing a dilute eluate, (typically mineral acid) solution through the bed to elute the contents from the 
resin The eluate stream must in turn be treated, generally to precipitate the ion of interest. Used at one 
molybdenum processing plant in US for waste water treatment (US EPA Development Document, 1982), 
see Section 4.3.2. 

principal advantages/disadvantages 

• high capital and operating cost 

• subsequent treatment of eluate required 

• resins and technique can be adapted to suit specific needs 

Potential 

Carbonate Precipitation 

The addition of limestone, soda ash or carbon dioxide produces metal carbonates with theoretical 

solubilities between those of metal hydroxides and metal sulphides. This treatment is most suitable tor 

effluents containing elevated nickel or lead concentrations which are the most difficult to remove by 

conventional lime treatment. 

principal advantages/disadvantages 

• solubility of some metal carbonates is lower than that of equivalent hydroxide forms, 
particularly for nickel, lead and cadmium 

• slow retention time 

• sludges more easily dewatered than hydroxide sludges 

• soda ash use three to four times the cost of lime for equivalent effects on metal removal 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-15/!.ecl3.rep/« 

Reverse Osmosis 

Reverse osmosis (RO) functions as the name implies, to move ions across a semi-permeable membrane 
under pressure, against a concentration gradient. The result Is that heavy metal waste streams become 
increasingly more concentrated while clarified water is discharged from the opposite side of the 
membrane. Reverse osmosis is used in various industries, for locaJ water purification, and to de-salinate 
sea water. RO Is apparently not used In the mining Industry for reasons of cost, and technical difficulties 
relating to the fouling of membranes which occurs in the treatment of alkaline solutions typical of the 
mining industry. The disposal or secondary treatment of the concentrate contaminant stream remains as 
a problem. Also, to be effective RO needs to be preceded by ultrafiltration (see below). 
principal advantages/disadvantages 

• very high capital and operating costs 
ultra-filtration required as a pretreatment 

• fouling of membranes would be a major concern, especially where hydroxide 
precipitation has been used for heavy metal removal 

Electrodiaiysis 

Electrodialysis utilizes membranes and is better suited than Reverse Osmosis to the treatment of 
concentrated waste streams. An ion exchange type membrane permits the migration of ions, within an 
electric field, from the dilute side, of the membrane to the concentrated side which functions according 
to Faraday's Law. A typical arrangement uses flat, square cells, spaced approximately six mm apart and 
stacked on top of each other, to form a module with a large membrane area. The spacing provides a 
short migration path and a high removal efficiency as wastewaters are pumped through at relatively high 
flow rates. The positive membrane pemilts negative Ions to pass and repels the positive Ions. The 
opposite is true for the negative membrane. As such, the arrangement of membranes and electrodes 
allows ions to leave the cell and not return. The process requires a large amount of electric energy and 
periodic replacement of membranes. As well the solution must be relatively free of particulate, i.e. 
electrodialysis, as with reverse osmosis, must be preceded by ultrafiltration 
principal advantages/disadvantages 

• limitation similar to those stated for reverse osmosis 

Ultra-Filtration 

Similar to reverse osmosis, ultrafiltration is a pressure-driven membrane process which is capable of 
separating solution components on the t)asis of molecular size and shape. Under an applied pressure 
difference across an ultrafiltration membrane, water and small solute species pass through the 
membrane and are collected as permeate, while larger solute species, including heavy metal 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3-19 



//p/3763-lb/sect3.rep/a 

precipitates, are retained by the membrane and recovered as a concentrate. Ultrafiltration involves 
solutes whose molecular dimensions are 10 or more times larger than those of the solvent. As a result, 
solutes with low molecular weight may be separated by complexing with larger macromolecules prior to 
filtration. A high rate of crossflow is needed to prevent build-up of solids on the membrane surface, and 
therefore the suspension is recirculated many times. Where cyanide is present, it is normally removed 
prior to treatment to assist in precipitate formation. Cyanide also tends to promote membrane 
deterioration. 

principal advantages/disadvantages 

• limitations similar to those stated for reverse osmosis 

Activated Carbon Adsorption 

Activated carbon can be used to adsorb selected metals such as cadmium, chromium, copper, nickel, 
lead and zinc. Adsorption from solution onto the carbon occurs as the result of the metal's lyophobic 
(solvent disliking) character relative to the particular wastewater stream. Adsorption also occurs as a 
result of the specific affinity of the solute, in this case heavy metals, for the carbon. The affinity may be 
either physical (as a result of van der Waal's forces or electrostatic attraction) or chemical In nature. 
Removal of these metals is therefore highly variable depending on the wastewater characteristics. The 
removal mechanism of heavy metals is thought to involve both adsorption and filtration (see Section 3.4 
Suspended Solids - Mechanical Filtration within the carbon bed. Carbon adsorption is used in the 
industry for gold and silver recovery, from strong and dilute cyanide solutions or slurries, but any 
adsorption of heavy metals is incidental to this process. We are not aware of any instances in the 
mining industry where activated carbon adsorption is specifically used to remove heavy metals as a 
treatment step. 

principal advantages/disadvantages 

• not as effective for heavy metal removal as some established competing technologies 

• high capital and operating costs 

• susceptible to fouling by lime scale and organics 

Electrowinninq 

Eiectrowinning is a physical process utilizing electrolytic cells in which an electric current causes heavy 
metals (including complexed metals, such as with cyanide) to deposit on steel wool cathodes or special 
extended surface area carbon electrodes. The electrodes are periodically transferred to a stripping cell 
where the metals are removed and collected on metal sheets. This process, while widely used for 
product recovery from strong solutions, has not (to our knowledge) been successfully used as a process 
for removing heavy metals from dilute wastewater solutions, due to process inefficiencies and high costs. 

3 - 20 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wvp/3763- 1 5/sect3.iep/a 

HSA Reactors Lid.. Toronto, piloted an electrochemical treatment plant in 1978-79 to remove heavy 
metals from waste tjarren (cyanide containing) streams, with the intent of not only removing heavy 
metals, but also to allow better re-use of barren solution. Although reportedly successful, the pilot plant 
work does not appear to have been followed up. 
principal advantages/disadvantages 

• pilot plant use linked primarily to cyanide recovery (i.e. by removing heavy metals from 
waste barren - cyankle solutions can be re-used) - other evolving methods of cyanide 
recovery appear more attractive (see Section 3.1) 

• not effective for removing heavy metals from dilute solutions 

Cementation 

Cementation can be applied to both dilute and concentrated solutions. This process involves 
percolating the metal containing waste water through a bed of scrap sacrificial metal such as iron. By 
oxidation-reduction reactions, the metal ions are cemented onto the sacrificial metal with some of this 
sacrificial metal going into solution. The process can essentially recover the waste metal In its pure 
form. After concentration the effluent may require treatment by other methods before release, 
principal advantages/disadvantages 

• not an effective technology for achieving the very low heavy metal concentrations 
demanded by current environmental standards 

Silicate Precipitation 

Sodium and potassium silicates interact with heavy metal ions forming insoluble metal silicate 
precipitates. Preliminary tests have recently been carried out by National Silicates Limited on the 
effectiveness of various modified silicates in the removal of dissolved nickel, zinc, lead and copper. 

These tests have been performed on synthetic solutions prepared from the dissolution of chemicals 
(analytical reagent grade) in de-ionized water. Parallel tests were run using: 

modified silicates 

lime 

modified silicate/lime in ratio of 40:1 

The results from these preliminary tests show that: 

. Maximum precipitation of dissolved metals was achieved with modified 

silicate/lime followed by, in order, modified silicate then lime. The solubility of the 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3-21 



«()/!/'(> J lb/becl3.rep/o 

metals was reduced by at least an order of magnitude when using modified 

silicate/lime as compared to the use of lime alone. 

Minimum solubility was achieved at lower pH's and over a broader pH range 

when using modified silicate/lime as compared to modified silicate and lime 

alone. 

Further investigation is planned on the treatment of actual industrial solutions, 
principal advantages/disadvantages 

this method shows promise but has not yet been evaluated above laboratory scale to 
determine applicability to the industry 

Bio-Fix Process 

The process has been developed by researchers at the U.S. Bureau of Mines for treatment of acid mine 
water. Biological matter with an affinity for heavy metals is impregnated on polymeric beads (Bio-Fix 
Deads) to improve the handling characteristics of the material. Placement of the beads In a waste 
stream (such as in a column or upflow filter) allows maximum contact with the waste stream. Removal 
of the adsorbed metals from the beads is accomplished by washing with acid. The process has been 
tested at laboratory scale and during at least one pilot scale program. Further treatment of the acid 
eluate solution requires development. 

principal advantages/disadvantages 

not sufficiently developed to allow evaluation 

operating/maintenance costs expected to be high 

3.3 ARSENIC 
Widely Used 

ferric chloride precipitation 

ferric sulphate precipitation 

hydroxide precipitation 

coagulant/flocculant addition 
Potential 

reverse osmosis 

ion exchange 

Arsenic, which may be present as soluble or colloidal anions in wastewater, requires a separate 
evaluation since its chemical behaviour is considerably different from other metals- 

3 - 22 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



vvp/3763- 1 5/sect3.rep/a 

Widely Used 

Ferric Chloride Precipitation 

The addition of ferric chloride to arsenic containing wastewaters converts both arsenite and arsenate to 
basic ferric arsenates, which are insoluble. However, there is still some debate as to the exact form of 
the precipitate produced, with some Indication that the adsorption phenomenon (arsenic adsorption onto 
ferric hydroxides and other species) is equally or more Important than basic ferric arsenate production, 
initial precipitation under slightly acidic conditions (pH 5), later Increased with lime addition, produces 
the best results. 

principal advantages/disadvantages 

one of the treatment systems of choice for arsenic removal 

effective, cost competitive, sludges (basic ferric arsenates) comparatively stable (subject 

to above qualifications) 

Ferric Sulphate Precipitation 

This method involves the addition of iron, in the form of ferric sulphate, to precipitate arsenic also as 
stable ferric arsenate. An iron dosage is normally maintained at an Fe/As weight ratio of greater than 
5:1 to maximize removal efficiency and ensure that the resultant sludge is stable. Commercial ferric 
sulphate can contain a large percentage of fen-ous iron which must be oxidized to ferric iron, since 
ferrous arsenates are more soluble than the equivalent ferric arsenates. Air mixing is therefore 
incorporated in the arsenic precipitation reactor to ensure that all ferrous Iron is oxidized to ferric iron. 
In German treatment plants visited, the chemical used Is ferricchioridesulphate obtained In liquid bulk. 
principal advantages/disadvantages 

unlike ferric chloride addition, requires aeration to ensure all iron is in the ferric form 
otherwise advantages are essentially the same as for ferric chloride 

Hydroxide Precipitation 

Addition of hydroxide either as lime or caustic Is used principally to remove heavy metals, but also has 
the indirect effect of removing arsenic as arsenic hydroxides and as adsorbed species onto other 
hydroxides. However, very high pH values, in the 11-12 range, are required. Precipitates are not 
particularly stable, and efficiency of removal is also quite variable, and poor compared with ferric iron 
precipitation. Lime or caustic alone are virtually never used In preference to ferric iron as a means of 
removing arsenic. 

principal advantages/disadvantages 

principal advantage is that metals other than arsenic can also be removed 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wu/J7b3 lb/sect J.rep/a 

comparatively high pH level Is required, removal not as effective as with ferric Iron, 

sludges are unstable 

not a treatment of choice for arsenic alone 

Coagulant /Flocculant Addition (In combination with precipitating agents) 

The addition of coagulants or flocculants enhances arsenic removal since arsenic precipitates, especially 
basic ferric arsenate, can be cdioidai and resist settling for subsequent removal and disposal. The 
controlled addition of coaguiant/flocculant in combination with mechanical settling provides this 
optimum removal of precipitated arsenic compounds, 
principal advantages/disadvantages 

typically used In combination with precipitating agents and/or reactor/clarifiers 
essential for precipitation of high density sludges at locations where treated effluents can 
not be combined with tailings solids to assist in settlement (such as at the OMOE's 
Deloro arsenic treatment plant) 

Potential 
Reverse Osmosis 

Reverse osmosis can be employed for arsenic in the same way as that used for heavy metal removal. 
Peter to Section 3.2 Heavy Metal Removal - Reverse Osmosis, 
principal advantages/disadvantages 

limitations the same as those defined for this process in Section 3.2 (Heavy Metal 

Removal) 

Ion Exchange 

Although different types of resins may be required, the ion exchange process for arsenic removal is 

essentially the same as for heavy metal removal. Refer to Section 3.2 Heavy Metal Removal - Ion 

Exchange. 

principal advantages/disadvantages 

limitation the same as those defined for this process in Section 3.2 

3.4 SUSPENDED SOLIDS 
Widely Used 

tailings ponds 
settling ponds 
sumps 

3 - 24 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/J/()3-)5/Gccl3.rep/a 

coagulants/flocculants 
mechanical settling 
Limited Use 

mechanical filtration (of slunies and sludges) 
mechanical filtration (of dilute suspensions) 
passive filtration 
engineered wetlands 

Widely Used 

Tailings Ponds 

Tailings ponds are almost universally used throughout the mining industry as a means of removal and 
storage of mill effluent solids. The only exception to this is the storage of tailings solids as a filter cake, 
a strategy employed at selected operations, notably in the United States. This practice is employed for 
site specific reasons and typically where conditions of net evaporation occur (e.g. the Mineral Hill gold 
mine in Montana). 

The effectiveness of tailings ponds for solids removal is readily apparent if one considers that the total 
solids content of the mill effluent is typically reduced from about 375 kg/rrf (30% solids by weight) to 
<.015 kg/mP. For settlement of tailings solids, comparatively short retention times (typically about 3-10 
days) are required. Longer retention times are required to allow for chemical process, and the 
coagulation and settling of extremely fine or colloidal particles. 

In terms of a design consideration, the critical factors are: (1) structural stability, (2) provision of 
adequate freeboard (normally 1.5-2 m), (3) spillway design, (4) protection of tailings pipe lines against 
mechanical damage and freezing, and (5) provision of catchment areas for containment of spills from 
pipelines. Tailings t)asins should also be designed to provide sufficient pond volume and maximum 
(normally 3-4 m) water depth to allow for effective settling under ice cover. Pond designs should also be 
such that the re-entrainment of settled solids due to wind and wave action is minimized. This may 
involve the use of either secondary ponds, or splitter-dykes within the tailings pond. 
principal advantages/disadvantages 

99.99+ percent effective for the removal of mill effluent solids 

with minor specific exceptions, universally used through the mineral processing industry 

high capital costs depending on site specific conditions 

provides for volatization of ammonia and phenolic compound breakdown 

generally low maintenance costs 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 25 



uvp/3763-15/sect3. rep/a 

provide control of other contaminants 

readily integrated into wastewater recycle strategies 

Settling Ponds 

Suspended solids in the form of fine tailings, as rock and as residual precipitates are generally removed 
by gravity In a settling pond. Settling ponds are frequently found in a series arrangement into which 
treated tailings water and mine water are discharged prior to recycle or final discharge to the 
environment. These ponds differ from tailings ponds primarily In size and in concentrations of influent 
solids. The size of the settling pond required for satisfactory removal of suspended solids relies on such 
parameters as particle size, pH and temperature of the water, wind and wave effects, depth of water, 
and inlet and outlet configurations. 

principal advantages/disadvantages 

universally used throughout the Industry for removal of suspended solids from mine 

water, for secondary settling of tailings pond effluent, and for the settling of sludges 

produced by waste water treatment plants 

comparatively low cost and simple maintenance 

very effective for most requirements provided that proper design considerations are 

taken into account 

often used in conjunction with other treatments and treatment aids 

Sumps 

In almost all mines, sumps are used to collect mine water that is typically high in suspended solids. The 
surplus provide surge capacity prior to pumping to surface and a method of removing coarse solids 
which would cause rapid pump wear. The clarified wastewater is pumped to surface and often 
undergoes further treatment. Suspended solids are periodically removed from the sump for disposal 
within the mine or on surface. 

principal advantages/disadvantages 

effective as a pretreatment to partially remove suspended solids from mine water, and to 

protect pumps from unnecessary abrasion 

no other practical alternative for this phase of operation 

Coaqulants/Flocculants 

The addition of coagulants and/or flocculants Improves the settling rate of precipitates or fine solids as 

floes are larger and consequently heavier. The process may be used in combination with systems such 



3 - 26 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



vup/3?63 15/secl3.rcp/a 

as settling ponds, mechanical settling devices or mechanical filtration or can be eliminated by filtering 
the floe solution and disposing the solids as a cake, 
principal advantages/disadvantages 

universal use with reactor/clarifiers to increase f)article size and settling efficiency 

occasionally used as an in-line effluent treatment 

wide variety of products available 

Mechanical Settling 

The equipment type is selected based on the flow range of effluent, the type of precipitate to be handled 
and the desired overflow (treated solution) clarity. Tanks are typically of concrete or metal and a 
rotating rake mechanism moves settled sludge from the bottom to a central discharge point. The 
performance of this equipment is frequently enhanced by the addition of coagulants and/or flocculants. 

Available types of equipment include thickeners, simple clarifiera, reactor/clarifiers, high rate type 
clarifiers. plate type (Lamella) clarifiers. 

Sludge produced by mechanical settling devices is frequently dewatered to improve handling 
characteristics or cost using various types of mechanical filtration equipment. The alternative is storage 
in a pond or lagoon where evaporation may assist in moisture reduction. 
principal advantages/disadvantages 

required for the production and settling of finely suspended and colloidal material, when 

sufficient retention and design characteristics are not available in tailings and settling 

ponds 

capital and operating costs do not always compare favourably with providing increased 

effluent retention times in tailings and settling ponds 

Limited Use 

Mechanical Filtration (of slurries and sludges) 

Removal of solids from slurries and sludges employs a variety of techniques dependent upon the 

material characteristics. Typical equipment types used are: vacuum filters, pressure filters, and 

centrifuges. 

principal advantages/disadvantages 

normally involved in process and product recovery, and in the dewatering of sludges, 

rather than as an effluent treatment per se 

not applicatHe to treatment of dilute solutions 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 27 



Mechanical Filtration (of dilute suspensions) 

In this method, wastewater is passed through a physically restrictive medium (filtration bed) which 
results in the deposition of suspended particulate matter. Filtration beds are generally composed of a 
mixture of granular media, such as sand or anthracite. As the load of suspended solids in the bed 
increases, so does the head loss, necessitating backwashing. During filter backwashing, the bed is 
fluidized and settles with the finest particles at the top of the bed. Subsequently, most of the solids are 
removed from the surface of the bed. Although gravity filtration is effective, pressure filtration has the 
advantage of operating at higher head losses which reduces the amount of wash water to be recycled 
and the size of the equipment. 

principal advantages/disadvantages 

application of this common waste water treatment technology to mining effluents is 

comparatively recent - normally in response to stringent site specific environmental 

standards 

effective as an add-on treatment step for removal of heavy metals following settling 

and/or mechanical clarification 

provision for backwashing allows for rejuvenation of the filter bed 

more expensive than conventional systems, such as settling, with higher operating costs 

sludge handling must be considered 

Passive Filtration 

Exf iltration is a type of passive filtration process whereby wastewaters contained in settling or tailings 
ponds seep through earthen dams or soils lining the bottom and sides of the pond and which act as a 
filtering mechanism. As the water seeps through, suspended solids are retained. This mechanism is 
effective during the initial use of the pond, but gradually becomes less effective as the soils become 
clogged, allowing little or no further seepage. Effluent control and monitoring is also sometimes difficult. 
principal advantages/disadvantages 

limited use as an engineered treatment system 

plugging/fouling of the filtration zone (typically sand) may require periodic removal and 
replacement of portions of the filtration bed - in the absence of backwashing capabilities 
exfiltration through the floor of tailings and settling ponds would be a temporary action 
becoming increasingly restricted by the deposition of fine solids - dependent upon 
favourable (coarse substitute) overburden and water table characteristics. 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



vvp/3763-15/sect3, rep/a 

Engineered Wetlands 

Wetlands encompass areas also known as marshes, bogs, wet meadows, peat lands, and swamps. 
Wetlands are generally used for mine drainage treatment with the goal of immobilizing pollutants for long 
time periods. Among the possit>le removal mechanisms are: 

filtering suspended and colloidal material from water through the soil 
uptake of contaminants into roots and aerial portions of live plants 

adsorption or exchange of contaminants onto soil materials, live plant materials, dead plant materials, 
or algal materials 

precipitation and neutralization by bacterial decay of biologic material which generate Nl-lj and HCO3 
precipitation of metals in the oxkdizing and reducing zones which are catalyzed by bacterial activity 
principal advantages/disadvantages 

most effective when used to modify and/or improve existing wetlands 

musky areas suitable for modification, wetlands in southern Ontario often provide critical 

habitats for wildlife and rare plants (e.g. orchids) 

iong-tenn implications of heavy metal accumulation relative to hazardous waste 

regulations (Regulation 309) need to be considered 

requires large land area 

3.5 AMMONIA 
Widely Used 

natural degradation 
Unique 

Homestake Method 
Potential 

air stripping 

steam stripping ' 

. biological nitrification - dentrifaction 

break-point chlorination 

ion-exchange 

electrodialysis 

reserve osmosis 
• alternative use of explosives 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 29 



wp/3763-15/sect3.rep/a 

Ammonia is generally found In mining wastewaters and originates from the use of explosive compounds, 
primarily from the ammonium nitrate - fueJ oil mixture (ANFO). Ammonia is also generated by cyanide 
breakdown, during processing operations, by natural degradation or by chemical oxidation. 

Other than natural degradation, which provides incidental treatment of ammonia, and the second phase 
of the Homestal<e method, there are no specific ammonia treatment practices used within the industry. 
The primary reasons are that treatment systems are expensive and not effective on dilute solutions. 

Widely Used 

Natural Degradation 

Natural degradation of ammonia involves the transpiration of dissolved ammonia gas from wastewaters 
by natural means by retaining wastewaters in holding ponds. Ammonia removal is enhanced by 
increasing pond area (ie. surface area), increasing pH. and by allowing for more contact with air. Refer 
to Section 3.1 Cyanide Treatment - Natural Degradation for other variables affecting natural degradation 
which are also relevant to ammonia. The pH/temperature relationship to the volatization of free 
ammonia is critical to the efficiency of removal. At neutral and lower pH values, most ammonia Is 
present in the NH^* form, which does not volatilize. 

Unique 

IHomestal<e Method 

The Homestal<e method of cyanide destruction, used at one plant in South Dakota, is described in 
Section 3.1. During the cyanide destruction phases, ammonia is created as a bi-product, as with nearly 
all other cyanide destruction processes. The second stage of the Homestake method is a nitrification 
step in which microbes (Pseudomonas pauclmobilis) convert ammonia to nitrate. Operation 
temperatures are ICP - 3(f 0. Effluent from the nitrification step, containing approximately 15-50 mg/L 
of suspended solids (primarily blomoss) is directed to a clarifier to remove this material. 

Limitations to the system include: temperature sensitivity, high capital and operating costs, as well as 
sensitivity to upsets. South Dakota experiences comparatively cold winters; however, the temperature 
limitation, in this case, is negated by the large proportion of warm mine water directed to the treatment 
plant. 



3 - 30 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3/63-15/sccl3.iep/a 

Potential 

Air Stripping 

Air stripping is typically performed in a pacl<ed bed tower with air flowing counter-current to tlie 
wastewater containing the dissolved ammonia gas. The transfer of dissolved ammonia gas from the 
liquid to air is enhanced by the packed bed which serves to maximize the surface area of the liquid 
exposed to the air. Nearly all pH levels of greater than 9 - 10 are maintained to convert ammonia in the 
wastewater to dissolved ammonia gas. As a result of the required high pH level, scaling can become an 
operational problem if sulphate or calcium (used for pH adjustment by the addition of lime) are present. 
Temperature of the water Is also important, as a decrease in water temperature increases the solubility 
of ammonia which in turn reduces removal efficiencies. 

Steam Stripping 

Steam stripping, used to remove ammonia, as well as volatile organlcs (see Section 3.7) from dilute 
solutions, is essentially a fractional distillation process, conducted in a packed tower or conventional 
distillation column. Lime is added to maintain a high pH critical to the effective removal of free 
ammonia. Wastewater Is preheated in a heat exchanger and pumped to enter near the top of the 
distillation column. As wastewater passes down the column, it is stripped by vapour rising from the 
bottom of the column. At the bottom of the column solution is further heated by incoming steam to 
reduce the final concentration of ammonia. Heat in the wastewater, discharged from the bottom of the 
column, is recovered by preheating the feed to the column. 

Biological Nitrification - Denitrification 

This method involves the biological oxidation of ammonia in a two step process. In the first step 
(nitrification), ammonia is converted to nitrite (NOj) under alkaline conditions, followed by nitrite 
conversion to nitrate (NO,). The second step (denitrification) involves the reduction of nitrate, to 
nitrogen gas and water, by contacting the solution with biological solids in the absence of oxygen at a 
neutral pH level. Carbon, in the form of methanol, is added to facilitate this anaerobic process. 

Break-Point Chlorination 

Breakpoint chlorination is a technique used to oxidize ammonia from wastewaters to nitrogen gas with 
the production of small amounts of nitrate and nitrogen trichloride. Chlorine, in the form of chlorine gas 
or sodium hypochlorite, is added to perform the oxidation process. Alkaline conditions are maintained 
by the addition of calcium carbonate which is required to neutralize the acid produced during the 
oxidation process. To eliminate hypochlorite toxicity in the treated effluent, sufficient retention is 
provided prior to discharge. 

OVERVIEW OF POTENTIAL EFFLUENT COfMTROL TECHNOLOGIES 3 - 31 



*p/3763-15/sect3.rep/a 

Ion-Exchange 

Ammonia can be removed from wastewaters by Ion exchange using resins which have a chemical 

affinity for ammonium cations. Refer to Section 3.2 Heavy Metal Removal - Ion Exchange. 

Electrodiaiysis 

Removal of ammonia can be accomplished by the electrodiaiysis method similar to that of heavy metals 

removal. Refer to Section 3.2 Heavy Metals Removal - Electrodiaiysis. 

Reverse Osmosis 

Reverse osmosis can be used to remove ammonia from wastewaters using membranes that are 

Impermeable to ammonia. For more details, refer to Section 3.2 Heavy Metals Removal - Reverse 

Osmosis 

Alternative use of Explosives 

The use of alternative explosives to limit ammonia in effluents Is considered to be best management 

practice rather than a treatment technology. Explosives use is discussed in Section 9. 

3.6 NITRATE/NITRITE 
Limited Use 

wetland filtration 
Potential 

denitrification 
ion-exchange 
electrodiaiysis 
reverse osmosis 

Nitrates and nitrites have not been identified as an effluent problem within the industry, nor are they 
monitored on a regular basis. For this reason, treatment systems for nitrate/nitrite removal have not 
been employed. The only exception is the incidental nitrate/nitrite removal achieved by wetland 

filtration. 

Limited Use 

Wetland Filtration 

Nitrates and nitrites can be removed from wastewaters by wetlands which can incorporate nitrate into 

their cellular structure, as well as to induce breakdown through microbial pathways. 

3 - 32 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-1 5/sect3.f ep/a 

Potential 

Denitrification 

Denitriflcation reduces nitrates arxJ nitrites to nitrogen gas using bacteria. Wastewater is passed through 
a mixed anoxic vessel, similar to a clarifier, containing denitrifying bacteria. A supplemental source of 
carbon, such as methanol, sugars, acetic add, or ethanol. Is required to maintain the denitrifying 
biomass. The denitrified effluent is then aerated to strip out gaseous nitrogen formed during 
denitrification that might otherwise Inhibit sludge settling. The resulting effluent is clarified and the 
sludge is collected for disposal or returned to the denitrification system. 

lon-Exchanae 

Ion exchange can be used to remove nitrates and nitrites from wastewaters by utilizing resins which 

have a chemical affinity for nitrate/nitrite anions. Refer to Section 3.2 Heavy Metal Removal - Ion 

Exchange. 

Electrodialvsis 

Removal of nitrates and nitrites can be accomplished by the electrodialysis method similar to that 

described for heavy metals removal. Refer to Section 3.2 Heavy Metals Removal - Electrodialysis. 

Reverse Osmosis 

Reverse osmosis can similarly be used to remove nitrates and nitrites from wastewaters using 
membranes that are impermeable to these compounds. For more details, refer to Section 3.2 Heavy 
Metals Removal - Reverse Osmosis. 

3.7 VOLATILE ORGANICS 
Widely Used 

tailings pond 
Potential 

air stripping 
steam stripping 

Volatile organics, are organic compounds with sufficient vapour pressure to allow their release to the 
atmosphere. In the mineral processing industry this would include petroleum-based and alcohol- based 
cleaning products and flotation reagents (e.g. such compounds as varsol, kerosene, and MIBC, etc.) as 
well as the breakdown products of these compounds. Volatile organics In final effluents were detected 
at few sites during the MISA monitoring program. 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 33 



Widely Used 
Tailings Ponds 

Tailings ponds provide a holding area with sufficient retention times to allow volatile organics to volatilize 
from the surface of the wastewater. Surface area, depth and temperature of the pond are therefore 
important parameters which dictate the rate of removal. This treatment is incidental to other tailings 
pond function, and does not reflect any specific attempt to remove volatiles per se. Refer to Section 3.1 
Cyanide Treatment - Natural Degradation for other variables affecting tailings pond function which are 
also relevant to volatile organics. 

Potential 

Air Stripping 

Air stripping of volatile organics is conducted in a packed tower and involves the transfer of dissolved 
volatile organics from wastewater to air which is flowing countercurrent to the wastewater stream. The 
process is similar to that described for ammonia removal. Refer to Section 3.5 Ammonia - Air Stripping. 

Steam Stripping 

Steam stripping of volatile organics is performed in a packed tower or distillation tower. The process is 

again similar to that described for ammonia stripping. Refer to Section 3.5 Ammonia - Steam Stripping. 

3.8 PHENOLICS 
Widely Used 

passive aeration 
Limited Use 

wetland filtration 
Potential 

chemical oxidation 

biological oxidation 

carbon adsorption 

Phenolic components can occur in tailings ponds as a result of their use as frothing agents (e.g. cresylic 
acid) They can also occur as a result of the breakdown of pine oil which is occasionally used as a 
frother in mineral flotation. Some collectors such as certain AEROFLOAT types also contain phenolic 
groups. The phenol content in tailings wastewater can therefore potentially be reduced by selecting 
other reagents if this is practical and economic (Section 8). Evaluation on a site specific basis Is 
required. Natural sources of phenolic compounds, resulting from the oxidation of decaying vegetation 

3 - 34 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-15/sect3.rep/a 

matter, especially the bark of certain tree species such as aspen/poplars, can also contribute to the 
presence of phcnolics Beaver ponds typically show elevated levels of phenolics. 

Widely Used 

Passive Aeration (tailings pond) 

Aeration in ponds or lagoons can provide a means of limited phenolic removal. Forced aeration is 
generally more effective in reducing phenolic levels than is passive aeration. The mechanisms for 
phenolic removal are not well understood, but likely include simple air stripping and degradation by 
biological action, possibly assisted by ultraviolet light. 

Limited Use 

Wetland Filtration 

Phenolic removal from wastewaters can be achieved by the utilization of wetlands as described under 

Section 3.4 Suspended Solids - Engineered Wetland. 

Potential 

Chemical Oxidation 

Chemical oxidizing agents, such as chlorine dioxide, hydrogen peroxide, ozone and potassium 
permanganate, will react with the aromatic ring of phenolic compounds resulting in its cleavage. This 
cleavage produces a straight chain organic compound which can be converted to carbon dioxide and 
water by additional chemical oxidation, or by other treatment such as biological oxidation. 

Biological Oxidation 

Phenolics can be biologically oxidized under aerobic conditions using heterotrophic bacteria that break 
down or hydrolyse organic ring compounds. Once the ring configuration is broken, the resulting straight 
chain hydrocarbon would be further broken down to carbon dioxide and water by bacterial activities to 
remove the organic matter from solution. 

Carbon Adsorption 

Phenolic compounds are readily removed by activated carbon from wastewaters of low phenolic 

concentrations. Refer to Section 3.2 Heavy MeXa\ Removal - Activated Carbon Adsorption for details. 

3.9 DISSOLVED SOLIDS 
Potential 

chemical precipitation 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 35 



wD/3763-15/sect3.rep/a 

ion exchange 

vapour connpression evaporation 

vacuum freeze concentration 

reverse osmosis 

electrodialysis 

membrane distillation 

Sulphates, carbonates and phosphates, as well as chloride, are the most prevalent dissolved solids 
(excluding metals which are discussed in Section 3.2) likely to be encountered in wastewater streams. 
Sulphates in particular can be present in very high levels. 

Potential 

Chemical Precipitation 

Depending on the solubility of the dissolved solids, most can be precipitated by the addition of various 

chemicals which react with the dissolved solids to form Insoluble compounds. Treatment technologies 

prevalent in other industries do not appear to be employed within the metal mining sector. 

Ion Exchange 

As dissolved solids are generally present as positive and negative ions in solution, ion exchange 
processes use both cationic and anionic resins to remove the dissolved solids from the wastewater. In 
typical processes, the cation exchanger replaces the dissolved positive ion with hydrogen ions while the 
anionic exchanger replaces negative ions with hydroxide ions. This process is most commonly used for 
removing dissolved salts from solutions having TDS (total dissolved solids) concentrations of less than 
500 mg/L 

Vapour Compression Evaporation 

Hot wastewater is sprayed over heat transfer tubes and a portion of the wastewater evaporates at the 
surface of the tubes to yield vapours which are compressed by a mechanical compressor. Compressed 
vapours then enter the heat transfer tubes where they condense and release latent heat. The latent heat 
is transferred through the heat transfer surface to the Incoming wastewater for evaporation. Condensed 
vapours are recovered from within the tubes as water, while the concentrated liquid phase from the 
evaporator forms the reject stream. This method is applicable to wastewater streams of high TDS 
concentrations. 



3 - 36 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



v«p/3763-15/scct3.rep/a 

Vacuum Freeze Concentration 

This method involves cooJlng wastewater to generate ice crystals consisting of pure water and a highly 
concentrated reject stream. In vacuum freezing, a vacuum is applied to reduce the boiling point of the 
wastewater to a level where the txjiiing point is the same as the freezing point. As vapours form, heat is 
released from the wastewater resulting in the production of ice crystals in the wastewater. The vapours 
are withdrawn and condensed to produce a pure water product The Ice crystals are separated from the 
concentrated liquid phase, vrashed and melted to produce additional water. The remaining wastewater 
is a concentrated reject stream. This method Is applicable to highly concentrated wastewater streams. 

Reverse Osmosis 

The most commonly used materials in typical dissolved solids removal applications are cellulose acetate 
and polyamide. The main factors which dictate the suitability of reverse osmosis in a particular 
application for the removal of dissolved solids are: 

1) the product water quality required 

2) the water recovery desired (ie. fraction of total volume to be treated) 

3) the ability to maintain the desired product flow. 

Commercially available membranes can reject from 91% to 99% of TDS from concentrated wastewaters, 
but use is partially dictated by the extent to which scaling by Inorganic precipitates may occur. Refer to 
Section 3.2 Heavy Metal Removal - Reverse Osmosis for further details. 

Electrodialvsis 

Electrodialysis is similar to reverse osmosis in that the factors dictating the suitability of this removal 
method for a particular application include: 1) product water quality required 2) water recovery desired, 
and 3) the ability to maintain the desired product flow. Generally, water recoveries of 85% or higher are 
feasible, however, wastewater streams with concentrations less than 15.000 mg/L would be the most 
applicable. Refer to Section 3.2 Heavy Metal Removal - Electrodialysis for further details. 

Membrane Distillation 

Membrane distillation is a relatively new process developed to remove TDS from aqueous solution. This 
process involves heating wastewater and passing it over one side of a highly hydrophobic, porous 
membrane. Pure water vapours pass through the membrane wall and are condensed to produce water. 
The hydrophobic property of the membrane prevents the liquid wastewater from passing through the 
membrane pores, while vapours freely pass through. The driving force for the process is the difference 
in vapour pressures which result from the temperature difference between both sides of the membrane 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 37 



w[)/3/63-lb/oc-cl3.rcp/a 

as hot wastewater is on one side of the membrane and a cooler atmosphere is on the other side to 
condense the vapours. This process would be applicable to low-volume, highly concentrated, high 
temperature streams. 

3.10 £H 

The supply of nutrients for plants, the release of substances toxic to aquatic life and the toxicity of 

dissolved substances (e.g. ammonia and metallocyanide complexes) are affected by changes In pH. 

The pM of wastewaters is adjusted by the addition of a base if the pH is too low and the addition of an 
acid if the pH is too high. The acid or base can be added as a liquid (e.g. sulphuric acid) or as a slurry 

(e.g. lime). 

The addition of an acid or base can be accompanied by the formation of precipitates. For example, the 
addition of lime to a wastewater contaminated with heavy metal and sulphate Ions results in the 
precipitation of metal hydroxides and gypsum, respectively. 

The chemical reagents used for pH adjustment are described below 

Widely Used 

lime 

limestone 
sodium hydroxide 

Limited Use 

sulphuric acid 
carbon dioxide 
magnesium hydroxide 

Widely Used 

Lime 

Lime is the most commonly used all<ali for increasing pH. The widespread use of lime is due to its high 

reactivity, its availability and its low cost. 

Lime is supplied as quicldime (CaO) or as slaked (hydrated) lime Ca(OH)j. The most cost effective 
choice between these two forms is dependent upon numerous factors which include the following: 

3 - 38 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-15/sect3.rep/a 

The geographical location of the effluent treatment plant with respect to the potential source of 

hydrated lime or quicklime. 

The reactivity, rate of slaking and expected variability In quality of the potential sources of 

quicklime. 

The expected rate of consumption of lime. 

Quicklime is reacted (slaked) with water to produce a slurry of hydrated lime using a grinding mill or 
slaking system. The slunv nomnally must be degritted before being used in pH control systems. 
principal advantages/disadvantages 

lime is readily available in bulk or packaged quantities 

low unit cost except where distant transportation Is required 

safe and easy to use 

Limestone 

The use of limestone instead of lime, to increase the pH of wastewaters is restricted due to limitations 

that include a slow rate of reaction, an inability to raise the pH much above 6.0 and its much lower 

solubility. 

Limestone and lime can be used in a two stage process to effectively adjust the pH of very acidic 
wastewaters (e.g. acid mine water). Limestone Is added to increase the pH to between 4.0 and 5.0 
followed by lime addition to achieve a pH In excess of 6.0. 
principal advantages/disadvantages 

safe and easy to use 

limited use for low pH range 

slow reaction 

Sodium Hydroxide 

Sodium Hydroxide is used to Increase pH. In can be supplied In dry form for dissolution at the site or in 
bulk as a concentrated solution. Sodium hydroxide Is appropriate for use when a rapid reaction is 
required or the presence of calcium ions Is undesirable. Where sulphate ions are present in solution, the 
use of lime will often lead to excessive scale formation. Sodium hydroxide solution may be preferable 
for small addition rates and where precise pH control is required. 
principal advantages/disadvantages 

• high unit cost compared with lime 

• the rate of reaction is much faster 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 . 39 



wp/3763-1t>/sect3.rep/a 

. no slaking or slurrying equipment is required 

• storage does not require continuous agitation to maintain homogeneity 

• safety and handling considerations 

Limited Use 

Sulphuric Acid 

Where required, sulphuric acid Is a reagent used to lower the pH of wastewaters. Sulphuric acid Is 
readily available, relatively inexpensive and its use Is characterized by fast reaction. The acid can be 
used as a concentrated solution containing up to 93% by weight. 

The storage tank must be surrounded by a dike and protective clothing is required when handling the 
acid. Safety showers have to be installed and be readily available to operating personnel, 
principal advantages/disadvantages 

health and safety limitations during handling 

close control of pH requires sophisticated controls to prevent overshooting pH target 

range 

Carbon Dioxide 

Carbon dioxide, in liquid form, is occasionally used to lower the pH of wastewaters. The liquid Is 

vapourized before being introduced into the wastewater. 

Carbon dioxide is readily available, safe to handle and ecologically safe, 
principal advantages/disadvantages 

health and safety benefits are much Improved over use of sulphuric acid 
application easily controlled 

Magnesium Hvdroxide 

Magnesium hydroxide can be used to increase the pH of wastewaters. Magnesium hydroxide Is 

sparingly soluble in water and is therefore used in slurry form. 

Magnesium hydroxide is used together with sodium hydroxide in a two stage process to raise the pH of 
a water effluent stream at the copper refinery of Noranda Minerals Inc. - OCR Division in Montreal East. 
This treated water is combined with cooling water and surface runoff before being discharged to the city 
sewer system. 



3 - 40 OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-15/scct3 rcp/« 

3.11 OIL AND GREASE 
Limited Use 

gravity separation 
air flotation 

Potential 

activated carbon adsorption 

Limited Use 

Gravity Separation 

Gravity separation is applied in the treatment of wastewaters containing significant quantities of oil. The 
separation devices are designed to provide sufficient retention time for the oil globules to rise to the 
surface of the water and coalesce. Baffles are provided to retain the floating oil and allow the passage 
of water. Skimming devices (e.g. scrapers, slotted pipes) are required to collect the accumulated oil 
prior to its disposal. 

Gravity separation is effective in removing and recovering unseparated emulsions and large droplets but 
is not as effective with finely dispersed small droplets or organic wetted particulates. 
principal advantages/disadvantages 

where required is cost effective and requires little attention 

Air Flotation 

Air flotation is applied to recover organics which are finely dispersed in liquid streams. 

The simplest device is the column type vertical cell. Finely dispersed organic solution droplets and 
organic wetted particulates are contacted by the rising air bubbles and can-ied to the surface where they 
are collected. Column type flotation devices do not require complex control and only require a small 
area for installation. 

Air flotation is also accomplished using dissolved air in two possible ways. In the first scheme, the 
wastewater is pressurized and compressed air is then introduced. The pressure Is released In a flotation 
tank, generating a fine dispersion of air bubbles. In a second scheme, air-saturated clarified water is 
introduced into the flotation tank under pressure through a micro-bubble nozzle as the pressure 
releasing device. Oil-grease and fine suspended solids attach themselves to the bubbles and are floated 
to the surface where a mechanical device is used to skim off the resulting sludge. 

OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 3 - 41 



wp/3763-1 5/sect3.rep/a 

principal advantages/disadvantages 

oil and grease levels generally too low to require treatment 
costs are greater than those associated with gravity separation 
sophisticated equipment 

Potential 

Activated Carbon Adsorption 

Dissolved organics are removed by passing the liquid stream through filter beds of activated carbon or 
anthracite, Specific pollutants are adsorbed on to the activated carbon surface until all active sites are 
occupied. At this point the carbon must be regenerated or removed and replaced. Regeneration is 
possible by either chemical (e.g. solvents) or thermal methods. Spent adsorbent which can no longer 
be satisfactorily regenerated can be disposed of as secure landfill or by incineration. 
principal advantages/disadvantages 

prohibitive costs and maintenance 

oil and grease levels generally too low to require treatment 

carbon retreatment or disposal required 

3.12 TOXICITY 

Acute toxicity testing is generally applied to fish species and to Daphnia species (water fleas). In 
Ontario and most other Canadian locations, trout and salmon are the test species of choice because of 
their demonstrated sensitivity to a wide variety of contaminants. In the United States, flathead minnows 
are commonly used for toxicity testing. 

Waste water treatment processes employed within the mining industry are generally directed at specific 
contaminants and groups of contaminants, as defined in Section 3.1 - 3.10, and not at toxicity per se. 
Tailings ponds pose an exception to specific contaminant reduction because of their general effects on a 
broad range of contaminants. 

The primary unknown in addressing toxicity, specifically, is in identifying the cause for toxicity test failure. 
Typically, toxicity results from individual contaminant toxicity, as well as from the synergistic toxic effects 
of several contaminants. Also, even with individual contaminants, such as copper, it is difficult to link 
toxicity directly to concentration because of the various ionic and solid phase species potentially 
present. Other site specific factors such as pH, temperature, hardness, complexing agents (naturally 
occurring humic and fulvic acids) also influence the toxicity of the effluent. 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



wp/3763-15/iect3.iep/o 

Information on the ability of the wastewater treatment technologies investigated, to pass the MOE criteria 
for trout and daphnia, was not available for this study. 

3.13 ZERO VOLUME DISCHARGE 

The United States Environmental Protection Agency (US EPA) defines zero discharge as 'zero volume 
discharge*. This concept differs from the objective of Ontario's MISA program, which is defined as 
'virtual elimination of persistent toxic pollutants'. Virtual elimination can be attained through either 'zero 
volume discharge' or through 'zero concentration' of contaminants. 

'Zero volume discharge' is practised by a large number of U.S. metal mining, milling and smelting 
operations, in locations where because of favourable climate, annual evaporation exceeds annual 
precipitation (net evaporation). Where net evaporation does occur, certain metal mining and processing 
sectors are required by US EPA regulations to achieve 'zero volume discharge*. Further details of the 
US regulatory approach are provided in Section 4.3. Operations located in much of Australia. South 
Africa, Chile and other arid areas are also able to achieve 'zero volume discharge' because of a 
favourable climate. 

In Ontario, 'zero volume discharge', even with maximum possible (100%) recycle is not feasible because 
Ontario experiences a net surplus of precipitation over evaporation, of from about 200 - 500 mm 
annually (Hydrological Atlas of Canada, Fisheries and Environment Canada, 1978). 

Technologies which work towards 'the virtual elimination of persistent toxic pollutants*, or have the 
potential to do so. are described in the preceding sections. Actual attainment of 'virtual elimination* 
through the reduction of contaminant concentration is not feasible with known technology. 



OVERVIEW OF POTENTIAL EFFLUENT CONTROL TECHNOLOGIES 



10^ 



10" 



3 10-^ 

5 



LU 

Q . 

^ 10"^ 



Pb (0H)2 



O 

g 10-^ 



oio-< 



10" 



10-^ 




PbS 




1 2 3 4 5 6 7 8 9 10 11 12 13 14 

PH 



Source: Metal / Cyanide Containing Wastes - 1 988 



Figure 3.2.1 

Solubilities of Metal Hydroxides and 

Sulphides as a Function of pH 





00 ^ 




































Ô 2 












































































































8 




































Q 










, 






1 








1 


1 










2 




































"■ 




































1 1 
Î I 

> o 










■ 






• 








1 


• 








: 




































1 


1 1 




































z 


































1 




































c 

8 


a 
1 


Î 














1 








. 


. 










E 


^ 














§ 


















^ 








































































.Ç 


Ï. 












, 












. 


Î 




f 


1 


1 


w 












* 














* 




5 


i 


Ô 




































i 


., 




























^ 




t 


Ô 


1 
















' 












i 




^ 


! 


r 1 


' 










1 




■ 








f 


1 


Î 


i 


1 


^ 




































K 


1 


Î 


1 


f 


i 


i 


1 


i 


3 


1 


i 


1 


1 


1 


• 


' 












































! 


5 


j 


I 


j_ 


1 
1 


Î 


1 

1 


J 


z 


1 

1 


1 


1 
f 


1 


! 


1 
1 





5 1 










^ 






















1 
1 


1 

i 


S 




















1 


>- 
1 


>• 

1 


i 


i 


1 






! 
















1 

1 


i 


















Il 

> o 




































i 1 
















i 




















1 




































1 




1 


1 








î 






















1 

< 










f 


î 
























II 

X E 


1 


1 


1 


1 




























1 






































1 
a. 


i 

a 

1 

E 


1 

1 


1 
î 
1 


a. 




i 
1 

1 


1 


1 
1 


i 
1 
1 


1 


1 


1 
1 


1 
1 


i 


1 

1 

E 

1 

Ê 


1 
S 


j 



wp/3763 15Aabo(con.fep/a 



SECTION 4 
EFFLUENT QUALITY STANDARDS AND REGULATIONS 



wp/3T6i- 1 S/sect4.rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

4 EFFLUENT QUALITY STANDARDS AND REGULATIONS 

Effluent quality standards and regulations are presented in this section for the geographic areas from 
which data on waste water treatment technologies were obtained, as well as from Italy and Spain. Limits 
from Italy and Spain are included, for reference only, and in the case of Spain, to indicate a different 
approach to regulatory limits. 

The main purpose for presenting these data is to provide a frameworl< against which the utilization and 
performance of world wide waste water treatment technologies can be assessed. 

In viewing the various limits and guidelines presented, some caution should be exercised to tal<e into 
account differences in quality control and assurance (QA/QC) procedures employed by the different 
countries and provinces. Ontario, under the MISA program, has adopted rather stringent QA/QC 
procedures in an effort to generate the most accurate data base possible. 

4.1 CANADA - FEDERAL REGULATIONS 

Federal 'Metal Mining Liquid Effluent Regulations' and 'Guidelines for the Control of Liquid Effluents from 
Metal Mines' were promulgated under the Fisheries Act in 1977. The 'Metal Mining Liquid Effluent 
Regulations' pertain to ail new, reopened or expanded mines from the date of promulgation. 'Guideline» 
for the Control of Liquid Effluents from Metal Mines' are non-regulatory and apply to mines established 
before 1 977. The regulations and guidelines do not apply to gold mines that use the cyanidation 
process. 

Both instruments specify the same numerical effluent quality standards for seven substances (arsenic, 
copper, lead, nickel, zinc, total suspended solids, and radium 226) as well as a lower limit for pH. A 
toxicity guideline (96 hr LC50 = 100%) is also established. Standards for the above parameters are 
outlined in Table 4-1 . Separate values are provided for grab sample, composite sample, and monthly 
arithmetic mean concentrations. 



EFFLUENT QUALITY STANDARDS AND REGULATIONS 



The regulations and guidelines apply across Canada as baseline standards. Provincial governments and 
other regulatory agencies may use these standards or impose more stringent criteria. This approach is 
typical of that used by certain other nations, most notably the United States. 

4.2 CANADA - PROVINCIAL REGULATIONS 

Ontario 

The province has jurisdiction over water supplies and discharges under the Ontario Water Resources Act 

(OWRA), the Environmental Protection Act, and other pertinent legislation. 

Primary control of mine effluents in Ontario is currently on a case by case basis through Certificates of 
Approval. The Ministry of the Environment's 1981 effluent 'Guidelines for Environmental Control in the 
Ontario Mineral Industry" have been used as a basis for determining limits. Effluent limits which are 
more stringent than these guidelines are employed at newer mills, and at older mills where process 
modifications have been made. In these cases 'Federal Metal Mining Liquid Effluent Limits' and OMOE 
Provincial Water Quality Objectives' for receiving waters may be used to drive site specific limits 

Quebec 

Directive 019 is a guideline for the mining industry published by the Quebec Ministry of the Environment. 

The effluent discharge limits outlined in the document are presented in Table 4-1. 

New Brunswick 

The requirements of the Federal regulations and guidelines are incorporated in Certificates of Approval 
issued pursuant to the Water Quality Regulation under the New Brunswick Qean Environment Act. 
These limits are also applied to a lead smelter. 

Manitoba 

The effluent limits contained within the Federal Metal Mining Liquid Effluent Regulations and Guidelines 
are the primary limits used in Manitoba. Limits are calculated from the Manitoto Surface Water Quality 
Objectives when more stringent standards are required to protect downstream uses. 

Nova Scotia 

An environmental assessment precedes application for an industrial permit under the Environmental 
Protection Act. The permit specifies limits for effluent discharge, which are normally based on: the 
Federal Metal Mining Liquid Effluent Regulations and Guidelines and as dictated by baseline information 
generated for the site. 

4 - 2 EFFLUENT QUALITY STANDARDS AND REGULATIONS 



wp/3763-15/sect4. rep/a 

Newfoundland and Labrador 

Newfoundland and Labrador use the limits specified in the Environmental (Dontrd (Water and Sewage) 
Regulations to control the effluent discharges to sewer systems and open water. These limits are 
presented In Table 4-1. 

Saskatchewan 

Saskatchewan's "Mineral Industry Environmental Protection Regulations' were created under the 
Environmental Management and Protection Act. Authorized concentrations of pollutants in liquid effluent 
are presented in Table 4-1 . 

British Columbia 

The Pollution Control Objectives for the Mining, Smelting, and Related Industries of British Columbia 
were formed under the Pollution Control Act. Discharges to water are controlled in the form of receiving 
water control objectives and objectives for the discharge of suspended solids and dissolved 
contaminants of final effluents to marine and fresh waters (Table 4-1). 

Alberta 

There are no metal mines in Alberta at this time. 

4.3 UNITED STATES - FEDERAL REGULATIONS 

Federal effluent limits for the ore mining category are designated by the Environmental Protection 
Agency (EPA) in the Code of Federal Regulations Title 40, part 440 (1989). Prior to 1984, effluent limits 
were based on the degree of effluent reduction attainable by the "Best Practical Technology Currently 
Available (BPT)'. In 1984, new limits were established for existing mines representing the level of effluent 
reduction attainat>le by the application of the 'Best Available Technology Economically Achievable 
(BAT)'. 

Further, BPT and BAT regulations (Code of Federal Regulations - 40 - Parts 440.32, 440.33, 440.102 and 
440.103, 1989) prohibit the discharge of wastewater from:(1) mines and mills which employ dump, heap, 
in situ leach or vat leach processes for the extraction of copper from ores or ore waste materials, and 
(2) from mills which extract gold or silver by use of the cyanidation process. This is the commonly 
referred to 'zero discharge ' criteria, where 'zero discharge' refers to 'zero volume discharge', as opposed 
to 'zero concentration of pollutants'. Relief from 'zero volume discharge' Is provided In net precipitation 
regions as follows: "In the event that the annual precipitation falling on the treatment facility (read 
tailings basin and associated settling/polishing ponds) and the drainage area contributing surface run-off 

EFFLUENT QUALITY STANDARDS AND REGULATIONS 4 - 3 



'A(ij/3763-15/5ect4.tep/a 

to the treatment facility exceeds thie annual evaporation, a volume of water equal to the difference 
between annual precipitation falling on the treatment facility and the drainage area contributing surface 
run-off to the treatment facility and annual evaporation may be discharged...' 

Additional restrictions on effluent discharge were placed on mines opened after 1984, which must follow 
New Source Performance Standards (NSPS). These limits represent the degree of effluent reduction 
achievable by the application of Best AvaflaWe Demonstrated Technology (BADT). Also, under these 
standards, process water from certain specified sources may not be discharged to navigable waters, 
including wastewater from: (1) mills using the acid leach, alkaline leach or a combined acid and alkaline 
leach process for the extraction of uranium; (2) mflls that use the froth flotation process for the 
beneficiation of copper, lead, zinc. gold, or silver ores; (3) mine areas and mill processes that use dump, 
heap, in-situ leach or vat-leach processes to extract copper from ores; and (4) mills that use the 
cyanidation process to extract gold or silver. 

Inspection of Table 4-2, together with the new restrictions, shows that emphasis on effluent wastewater 
control for new plants is placed on effluent volume control, rather than effluent concentration control. 
Relief from 'zero volume discharge' for new plants subject to NSPS is the same as that applied to older 
plants using BPT and BAT technologies 

4.3.1 The Concept of 'Zero Volume Discharge' 

Zero volume discharge' is achievable for a large number of US mineral processing facilities, because 
many such facilities are located in dry climates. This is particularly true of gold and copper producers 
(see Sections 6.1.3 and 6.2.3). Also, even in instances where there is a slight annual excess of 
precipitation, over evaporation, zero volume discharge Is potentially achievable due to the retention of 
water in tailings voids, provided that a high degree of recycle Is practised. 

Impetus for zero volume discharge in the drier portions of the United States derives from concerns over 
protection of fresh water as a limited resource. 'Zero volume discharge' in Ontario is not feasible 
because annual water surpluses across the province range from about 200 to 500 mm. 

4.3.2 UNITED STATES - STATE REGULATIONS 

As in Canada, individual states may choose to enforce effluent quality standards which are more 
stringent than EPA standards. This Is currently the case with some lead producers in Missouri as well as 
with producers elsewhere, such as Alaska and Michigan (see Section 6). 



EFFLUENT QUALITY STANDARDS AND REGULATIONS 



wp/3?63-1b/sect4.fep/« 

A further point of note relative to state versus federal Involvement, Is control of cyanide concentrations. 

US EPA regulations regarding the discfiarge of cyanide containing wastewaters are derived from the US 
EPA 1982 Development Document for Proposed Effluent Limitations and Guidelines - Ore Mining and 
Dressing . This document was prepared in the interval from 1979 to 1982. At that time, many of the 
cun-ently recognized cyanide destruction technologies were unproven beyond the 'bench scale'/pllot 
plant level. This circumstance, coupled with the fact that nearly all gold mills were located in arid zones, 
made it expedient to adopt the 'zero volume discharge' criteria for cyanide wastewaters - and to refrain 
from defining an acceptable limit for cyanide in mine/mill wastewater. 

Since 1982, there has been little impetus to reconsider the possible role of cyanide destruction 
technologies in effluent treatment. As a result, It still remains that there Is no EPA limit for cyanide. 
Therefore, in cases where net annual precipitation exceeds evaporation and relief from 'zero volume 
discharge' is provided, an appropriate limit is set by the state. 

4.4 EUROPE 

The Commission of the European Communities is currently undertaking studies for the purpose of 
developing standard effluent limits across Europe by 1992. Until that time, each European country will 
continue to follow their existing effluent limits and/or guidelines. Limits for several European countries 
are listed in Table 4-3. Canadian limits are retained in the table to facilitate comparison. Contemporary 
European standards are generally comparable with Canadian standards. 

Sweden/Norwav/Finland 

Mine, mill and smelter effluent limits are determined on a case by case basis throughout the whole of 
Scandinavia. Notwithstanding state/provincial discretion, this is in contrast to the US condition, and to 
conditions in much of Canada where there is a move towards standardization of limits. 

In Sweden, for example, effluent levels are determined by an impartial judicial body, with representations 
being made by both the company and by the Ministry of the Environment. On the basis of these 
representations, the judicial body will set limits with the objective of approaching the guideline values 
shown In Table 4-3, to the extent practicable. Site specific effluent loadings are frequently applied in 
setting effluent limits and limits may In fact be expressed as loadings rather than as concentrations. 
Environmental, technical, economic and social concerns are all taken into account. For example the 
Falugruva Mine v/as able to reduce the level of zinc in the wastewater from 1000-2000 mg/L to 1 mg/L. 



EFFLUENT QUAUTY STANDARDS AND REGULATIONS 



wp/37b3-15/sect4.rep/a 

A zinc level of 1 mg/L was subsequently accepted by the Swedish EPA as a monthly standard for this 
operation. 

Also, if it is determined that more stringent standards are desirable than the company Is able, or 
prepared, to meet, then a type of 'control order" may be Issued whereby the company is given a set 
period of time to determine whether or not more stringent standards can feasibly be met. 

In Norway, permits required by mines under the Pollution Control Act stipulate the wastewater treatment 
program which must be achieved. Mines are required to monitor the receiving water body to ensure 
that water quality objectives are being followed. There are no set contaminant limits on effluent 
discharges, each being determined, as indicated, on a case by case basis. 

Conditions in Finland are much the same as in Sweden. Limits on wastewater discharges are site 
specific. The principle considerations in determining the appropriate limits are the initial and achievable 
contaminant levels and the available methods of wastewater control. 

Germany 

In Germany there are both federal and regional limits. The regional limits tend to be similar to the 

federal ones and often include additional parameters and site specific limits. 

France 

In France, the maximum cyanide level of wastewater from gold mines is permitted in the range of 

between 0.5 and 2 mg/L, depending on the mine location and effluent discharge point. 

Spain 

Spain's Regulation Concerning Public Waters is administered by the Environmental Agencies of the 
provinces and defines the maximum permissible limits for effluents discharged to a public waterbody by 
any municipal or industrial discharger. These limits are divided into three categories (1), (2) and (3) with 
decreasing concentrations (Table 4-3). The quality of effluents being discharged to public waters is 
compared with these tables, from which a tax on the discharger can be assigned. If the concentration 
of any parameter in Table 4-3, Column (1), is exceeded in a discharge, the discharger is required to treat 
the effluent or be shut down. 



4 - 6 EFFLUENT QUAUTY STANDARDS AND REGULATIONS 



wp/3763-15/sect4.rep/a 

Italy 

Federal limits for effluent discharges in Italy are outlined In the 'Regulation for the Protection of Water'. 

under Regulation #319. These are presented in Table 4-3. 

4.5 AUSTRAUA AND NEW ZEALAND 

The environmental control of operating mines in Australia, including wastewater controi, is regulated by 
the individual states. The effluent limits which must be met in Tasmania are included for reference in 
Table 4-3. Standards vary mart<edly from state to state, sometimes by as much as an order of 
magnitude, in most states other than Tasmania 'zero volume discharge' is practised due to climatic 
conditions. 

r^letal Mining Operations in New Zealand are restricted to two recently commissioned gold mines, 
namely Waihi's Martha Hill Project and Cypms Gold's Golden Cross Project. Effluent limits are set on a 
case by case basis, determined essentially by receiving water characteristics and overall environmental 
sensitivity, and are among the more stringent encountered for certain parameters. For example, CN ^^^ 
and total copper limits are set at 0.67 mg/L and 0.05 mg/L respectively. Sand filtration is practised as a 
final polishing step to further reduce heavy metal levels, particularly that of copper. 

4.6 OVERALL COMPARISONS 

In reviewing Tables 4-1 through 4-3, for the key parameters of pH, suspended solids, cyanide, and heavy 
metals, there is considerable variability in applied standards and guidelines for certain parameters, and 
general similarity for others. The most comprehensive set of standards is that used by British Columbia. 
Generally the most stringent standards for metals are those used by Sweden and New Zealand. 

In the case of Sweden, guidelines shown, as indicated, are ideal standards which companies may, or 
may not, be asked to achieve, depending on circumstances. The Vieile-Montagne lead/zinc mine and 
milling operation, for example, is currently meeting 0.4 mg/L for zinc, but has been asked to investigate 
possible means of reducing zinc concentration to the 0.1 mg/L guidelines (Mr. Fred Mellberg. Vielle- 
Montagne, pers comm). 

On a parameter by parameter tasis, the following can be deduced from the tables. 

£H 

Most operations worldwide are required to achieve final effluent pH in the range of 6.0 - 9.5, with 
extreme limits of as high or low as 10.0 and 5.0 in some instances. 

EFFLUENT QUALITY STANDARDS AND REGULATIONS 4 - 7 



wp/)/r,3 15/&eci4.rcp/a 

Suspended Solids 

Ontario and Sweden are the only jurisdictions examined which specify a suspended solids limit of 15 
mg/L Otherwise, 20-25 mg/L is the lower long-term average limit used by most countries/regions. 
Maximum acceptable values generally range from 30-50 mg/L 

Cyanide 

Cyanide is controlled as b)Oth total cyanide and wesik acid dissociable cyanide (WAD). This parameter, 
perhaps more than any other is most variably regulated. Limits for total cyanide range anywhere from 
G 025 - 2.0 mg/L Limits set in the United States, typically 5-50 mg/L are related to wildlife/bird toxicity 
and to zero volume discharge requirement, and are therefore not applicable to Ontario. Gold mining in 
Europe is virtually non-existent (other than that which Is Included with t)ase metal concentrate 
production). A limit of 0.5-2 mg/L for France is shown, which relates to one mine. The lowest level, 
025 mg/L for Newfoundland, appears to be based on plating industry standards. The one 
Newfoundland gold mine, Hope Brook, was unable to meet this standard. Hope Brook Is currently not 
operating. 

Cadmium and Mercury 

Cadmium levels of about 0.02 - 0.2 mg/L are typical of most countries and regions. Ontario's standards 
of 0.001 mg/L, are markedly more stringent. Mercury levels of O.OOi - 0.005 mg/L are typical, with 
those of Germany at 0.05 mg/L t>elng the least stringent. 

Copper 

Typical allowable copper concentrations are in the 0.15 - 0.3 mg/L range, with some limits above and 

below this range. 

Lead 

Long-term average acceptable concentrations for lead, are more uniform than those used for many 
parameters, typically being in the 0.2 - 0.3 mg/L range. However, lower standards to about 0.05 mg/L 
are imposed by British Columbia, and Missouri. British Columbia standards apply to the dissolved level, 

not total. 

Zinc 

Accepted effluent levels for zinc are generally In the vicinity of 0.50 mg/L. The lower guideline shown for 

Sweden is a desired objective with recognition that this standard may not be achievable In many cases. 



EFFLUENT QUALITY STANDARDS AND REGULATIONS 



wp/3/G3-15/5CCl4.rep/a 

Nickel 

Nickel limits are also typfcally in the 0.5 mg/L range. Limits were not set for nickel by the US EPA 
because there Is only one operating nickel mine In the U.S., and because limits set for copper and zinc 
are thought to be sufficient to control nickel concentrations (US EPA Development Document for Effluent 
Limitations Guidelines and Standards for the Ore Mining and Dressing Point Source Category - 1982). 

Arsenic 

Long term average acceptable concentrations typically range from 0.1 - 0.5 mg/L, 0.5 mg/L being the 

norm. 

4.7 QUALITY ASSURANCE AND QUALITY CONTROL fQA/QC) IN LABORATORY TEST WORK 

Certification of laboratories Is not legally required in Canada. However, it is common practice for many 
laboratories to become certified through the Statistical Council of Canada or the ACLAE-CAEAL 
(Canadian Association for Environmental Analytical Laboratories). Many laboratories also participate in 
interlab studies to verify the accuracy and precision of analytical results. It is expected that at some 
time in the next few years certificatton of laboratories will become compulsory. 

Ontario is the only province which has developed a guideline (Code of Practice for Environmental 
Laboratories) which outlines standard QA/QC procedures. The document provides options for particular 
tasks as opposed to describing one particular method which must be followed. Topics addressed in the 
guideline include: management responsibilities, quality management principles, laboratory organization, 
physical facilities and services, sample and workload management, analytical systems, analytical 
methods, analytical control, data reporting, and records and data management. 

British Columbia requires that all laboratories take part in a lab registration program and a split sample 
program (twice per year). The Ministry of the Environment recommends that industry use certified 
laboratories, however laboratories are not legally required to meet any specific criteria or to be certified. 

Saskatchewan does not have formal gukJelines for QA/QC programs but keeps informed of the QA/QC 
plans used by laboratories by requiring 'An update on the ongoing QA program for the field & lab 
procedures performed by both field staff & analytical laboratories" in the Approval to Operate. 

Alberta is presently In the development stage of addressing the laboratory certification issue. Currently, 
the Ministry of the Environment requires Industry to use an 'acceptable' laboratory. A copy of the 



EFFLUENT QUAUTY STANDARDS AND REGULATIONS 



uvp/3763-15/sect4.rep/a 

laboratory's QA/QC program must accompany the results. This is used by the Ministry to verify the 
acceptability of the laboratory. 

Nova Scotia. New Brunswick, Newfoundlarxi. and Quebec encourage, but do not legally require, 
laboratories to obtain certification. 

United States 

In the US, the state decides whether laboratories must be certified and, if so, by the US Environmental 
Protection Agency or the state. Certification by the EPA includes monitoring with sample checl<s and 
site visits by EPA officials on a regular basis. Certification ensures that the laboratory is using approved 
methods for sampling and analysis and Is fulfilling all other regulatory requirements. 

EPA certification consists of a QA plan which consists of: a project description, proJect organization and 
responsibility, QA objectives, sampling procedures, sample custody, calibration procedures and 
frequency, analytical procedures, data reduction validation and reporting, internal quality control checks, 
performance and system audits, preventative maintenance, specific routing procedures used to assess 
data precision, accuracy and completeness, and corrective action and quality assurance reports to 
management. 

Laboratories must also have an analytical quality control program. Recognized internal and external 
quality control methods are used to evaluate the accuracy and precision of the analytical data. Water 
blanks, spiked blanks, travelling blanks, reagent blanks, calibration standards, spikes, and duplicate 
samples are analyzed routinely. The results from these analysis must be periodically checked, tabulated 
and summarized graphically, and be available for inspection when required. Method repeatability must 
also be verified by calculating the standard deviation of a series of replicated measurements 
representing know QC solutions and skilled analyst perfomiance. 

In general, EPA requirements are applied across the United States. The most common difference 
between states are the standard methods which are used. The State of New York for example has 
developed some of their own methods in addition to the EPA methods. In the State of Missouri, no 
certification is required however, standard methods from the EPA, ASTM, and the Standard Method 
Manual of Waste Water must be followed. 



EFFLUENT QUALITY STANDARDS AND REGULATIONS 



wp/3763-15/secl4 rep/a 

Europe 

The European Community Commission (ECC) has established standards, document #45001 'General 

Criteria for the Operation of Testing Laboratories*, for the certification of laboratories within the European 

Community. 

Sweden requires that all laboratories which do analysis related to the environment to be certified. Either 
ECC or Swedish Standards may be followed to meet certification requirements. 



EFFLUENT QUALITY STANDARDS AND REGULATIONS 



-1 








o 


q 




S 


q 


5 


q 












, 
































< ê 
































ANAD 

compos 






« 


in 


Î2 




s? 


}S 


«? 


le 
















î; 


•{? 


d 




«* 


d 


d 


d 












O 
































II 






q 


q 


m 




1 


m 


w 


m 
















S 


•? 


d 




o 


d 


d 


d 












O 
































z 








































o 
























§ 


i 


i 


8 


d 

1 


S 




s 


S 


CM 

d 






q 








Q 


o 


d 




"î 
















d 








u. 








m 
























5 
































UJ 
































z 
































z ^ 








o 
























1 








d 
























UJ 1 








q 




q 


q 


<! 


q 




q 








o "= 








ui 






d 




d 






CM 








1- 
































































(/> 








u> 
























< « 

V) 1 








d 


m 

d 




2 


in 

d 


1 


2 




q 








< 
































œ 








o 
























S 


^ 


i 






q 


S 


s 


o 


C4 


q 


q 


m 








II 


d 
1 

i 


1 


d 
in 

î 

d 


1 
o 

d 


d 
Î 


d 
Î 


1 

2 


d 


1 

2 


2 


d 
d 








m 
































o 
































a 

2 






q 


«n 


S 




8 


S 


o 


S 


g 


? 








o 






c2 


d 


d 




d 


o 


«=> 


d 


ri 










g 








































(O 
























<« 








o 






« 


«n 


<1 


« 




q 








g* 


1- 


T- 




^ 






s 


s 


S 


S 




î^ 


S 






z 


s 


s 




J> 


m 




q 


q 


q 


q 


q 


q 


m 


q 


o 


o 


d 


'- 


in 


d 




'-" 










CM 


o 
































,^ 






oc 






^i 




1 


1 
















i 


M 


< 


s 


ï 

s 


î 

(A M 


i 


2 
S 


^'1 


5 


5 


I 


^ 


1 

2 


n 


« 


8 

m 


Jl 



■•f 

jlf 

if 










n 
























o 
z 

z 
































i 


11 

X 

i 

V) 1 


































< 
5 

ri 


S 

o 


1 

1 


b 


1 

1 
9 


q 

S 

b 


d 

i 


lO 

b 


1 

5 


b 


m 

1 
m 

b 


1 
1 


1 

1 


b 

o 


b 




i 

ex 


o 

UJ 

m 

§ 






























b 




O 

Z 

o 








o 


























oc 

ILI 

a. 


la 

o Q. 


E 


[1 


z 

s 

1- 


^ 


ï 


S 


u. 


1 
1 


o 

S 


iî 

= z 


II 


I 


J 


£ 
u. 


II 



^1 

z 



CANADA • 

monthly composite grab 
mean sample sample 1 
































1 


O 

z 
z 








s 








A 


h- 

2 


tn 


o 


5 


q 


o 


6 










q 


s 




2 


q 

m 

d 




















< 

03 

1: 


5 

CM 


q 

m 
1 




























1 
œ 


o 

Ui 

to 

s 


































Ï- 




5 






























ce 

t 


J 


i 

1 
Ô 


5 




li 


o 

11 


o 9 

il 


2 

f 
i 


S 


> 
If 

ô » 


s 


o 
m 


Ô 


1 

9 


1 

i 

O 


"S 
o 
















— 


— 


— 


t 






8 


m 


iC 


o 




8 


s 


S 


o 

O) 


6 


d 


d 


d 




d 


£ 




o 














i 




<b 


o 


S 


lO 


(D 




§ 


E 


s 




5 


d 


'■ 


d 




o 


S 






8 


« 








S 








d 


d 


d 


o 




d 






































s. 


















i 






o 


§ 


q 


<P 




i 


E 






6 


d 








d 


? 






8 


!? 


S 


t? 




8 


a 






o 


d 


d 


o 




d 


P 






o 


o 








§ 








ih 


P 




(0 




^ 






6 


o 


'" 


d 




d 


d> 






S 


«5 










CO 




q 


6 


d 


d 




o 




S 




1 


















O 














^ 




<b 


o 


o 


q 




q 




^ 






5 


° 










? 






8 


«5 










a 


s 


q 


6 


d 


d 




d 




S 






















o 














i 




(b 


o 


o 
















n 


q 




q 




E 


s 




d 


d 










CT 
















~ 


â 


_ 


















o 


0) 
































'^ 




Q 














i 


s 


<ô 














i 




O 


8 


Ï2 






U) 






s 


oi 


d 


d 


d 


d 


d 




2. 




o 














1 




(6 


o 


o 


q 


«> 


q 






s 




d 


o 




q 






t 




o 


8 


« 








8 


S 


g 


<B 


o 


d 


d 


o 




d 


s 
£ 




» 


o 


S 


q 


(O 




i 




s 




d 


d 




d 




d 


f 




S 




Ï2 


le 






"7 




a 






d 


d 


S 




d 


1 




S 




S 


J 


<o 




i 




_§ 


^'^^ 


'^^ 


d 


_EI 


d 





o 


















^''^ 


a 


il 

TB II 




1 


1 


I 


5" 
1 


1 


1 


Q. 


1 il 


X 


O 


3 


^ 


f 


i 


? 



o T5 



ff 

if 
c ce 

li 

II 

« I 

i - 
^5 
II 

II 

lit 

lif 

m 

o a s 
§ 2 S 



" S s o 

•o S o Ç o 

1 ê 8 S g 
3 £ 1^ ? 2 
§. S f o. 8 



Il 



f II 

oo E E 
> S 2 

13 T3 -o 

2 S- §> 
o s s 

i I I 

^ I 2 
§11 

K o o 
Z Q. O. 

Q ^ •S 



i i i 



Ë ? i 

Ê Ê I 

E E i2 

Il 1 

n> <a o 

c c J: 

« ? TJ 

^ ^ S, 

» g s 

= £ =5 



o o o 

1 5 -S c ^ 

i= i= i a tj 

c c c 5 c 

S 8 S S S 

c c c a c 

8 8 8 S 8 



S ë" 

o -R 



lî 



II 
III 

y 5 I 



< ^ ^ 

sll 

ill 

j. s TJ 

osa 



m 

o o ô 



o o 
c c 

ïï s s 

III 



II 



II 



5 8 



il 



il 



§ s 



z S 



en 


a 






8 


«2 


•0 




6 












ni 


i 































■5 






a> 


























^^ 





























































i 






<o 


























t 


8 




























•5 






























^"^ . 


s 





























i 






» 


























8 







8 

d 






















r 






d 


d 

















































i S 





























































^ 











































m 








8 













r 


R 



























E 




























































e E 






















ç 













^ i 


8 




<b 














« 





8 


•«■ 
























8 













r 























2 






•i >D 





















^ 


„ 






























d 





<«• 




= i 






























? 


8 










6 




5 




P 










1 








P 
























3 






o> 
























i Si 


R 











P 




s 






° 


8 




































E 






























? 


8 










d 








8 


« 


? 


« 






8 




p 








q 








§ 





8 


V 




. . 






<0 
























i 


8 


5 



























g 































































i 






(C 












































































j 






1 


i 


1 


j 




, 




, 


? 
? 


1 




Q 


j 


i 

■5 
s 


f 






\jî 


i 


Ê 


S 


3 


.5 


Ê 


5 


? 






J: 


3 


i 



II 



j il 

I I f 

Ml 

îil 



il 



ilU 



s 1 



§ I 



1 1 



5 z 



il 



If" 

II! 



1 1 ë 

o 01 È. 

Ill 



III 



? ? I 

2 2^ 



III 

â â o 

•5 ô g 

Ills 
I I ë s 
ë ë s s 
s s $ s 



I 
i 

f 

I 
II- 

l!i 

i § l 

III 



ë 

If 



I s ? < s 

ills I 

E & * s -6 

I 5 ë - ë 

£ < 1 s 1 

ï 5 £ ^ £ 
5 ^ » .^ » 

5 y P g ? 
« i 1 â K 

I 8 e I ^ 
f > I !^ t 
I 8 I g I 

ï i â I â 

s I B œ o 

^ ë S i I 
I a I ff I 



5» 


1 


o 
b 


6 


■ 




d 




o 


o 


8 

d 










B 


d 














<1 - 














































H 














































^ 


5 


§ 






8 




8 


p 


8 








° 


S 


















a 












o 




o 




























■£ 




























































































S 


o 




8 




d 


" 


s 


2 




CM 










ïî 




1 


d 


'■ 


CM 


CM 






Ol 




S 




CM 


o 


lO 


m 




n 










S? 




ç 


m 


^ 


O 


en 


< 


f^ 


o 




O) 


o 




o 


o 
















^ 


° 






















































v> 










Iri 






































£ 


d 




8 




•n 


8 


q 


o 




o 










8 




i 


q 


CM 


* 


o 






S 

6 


in 


S 


m 


CVi 


m 


lO 




CM 


CM 


m 






m 










<NJ 




CM 


^ 




8 

b 


Jj 


o 


o 


o 






























t 






















































8 


. 




o 




„ 




O 








ir> 






ç> 








„ 


S^Ta 












1- 




o 


















a 








1 










o 










i 




s 














i 






















^ 


^ 




^ 




^ 


tfi 






















z 












o 


o 




o 




o 


o 






















o 














































^ 














































If 




3 


8 

6 






d 


- 


d 


d 


d 


in 
d 








d 




- 


























































CC gl 














































o^ 














































^ 




pj 


S 

6 






m 


^ 


^ 


lO 


^ 














^ 












ll" 














o 




d 


























o-- 






















































o 


o 


V 


o 


o 


u> 




o 




o 






















H 






s 




o 






o 








s 




































































m <B 






m 


m 


n 


lO 


m 


S 




m 




„ 




















< 

z 


n 










o 


d 


d 




d 




s 




















u 


p 






S 


o 


o 


d 


d 


d 




d 




° 


















































































































i" 






« 


















û- 
n 






















cr 






S 












^ 






ii= 






















c 


















1 




1 


s 


^ 




z 


a 


o 






'^ 






j_ 


S 


5 




I 
a 


f 


c 


4? 


5 


Ô 


z 


'S 

J 


j 


ô 


§ 


1 


1 


1 

î 


1 
1 


5 


ê 


£ 



wp/J /6 J- 1 b/Tobolcon.f ep/a 



SECTION 5 
SCREENING OF WORLD WIDE OPERATIONS 



IMP/3 763-15/3ectS.rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

5 SCREENING OF WORLD WIDE OPERATIONS 

5.1 ONTARIO PROCESSING PLANTS 

Data available from the MISA monitoring program togetlier with published information and information 
obtained through personal communication with a number of mining and milling operations, was 
generally sufficient to determine which operations should be included in the inventory of selected 
operations (see Section 6). 

For gold operations in Ontario, wastewater treatment facilities are as advanced and diversified as any in 
the world. Also, a comparatively large proportion of Ontario's gold operations are recent or modernized 
developments, and therefore have had opportunity to employ the latest and most advanced wastewater 
treatment technologies. For these reasons, a large number of Ontario gold operations are included in 
the inventory. 

This is somewhat less true of base metal milling/smelting operations, which, except for nickel producers, 
are far fewer in number, and for the most part, tend to be older operations. 

There are no remaining active silver producers in Ontario (apart from secondary production associated 
with operations such as the Kidd Creek smelters). Iron and uranium producers are confined to the 
Algoma Ore Division (in the case of iron), and to Denison's Elliot Lake Mine and Rio Algom's Stanleigh 
Mine (in the case of uranium). The latter three operations are included in the inventory to provide 
representation of Ontario operations. 

5.2 CANADIAN PROCESSING PLANTS OUTSIDE ONTARIO 

Selected Canadian mines/mills and smelters, existing outside of Ontario, were contacted by telephone 
and questionnaire, for the purpose of inventory development (see Section 6). The choice of processing 
plants was t)ased on: experience and knowledge of Canadian operations by Kilborn and BAG staff 
(including that of branch offices and related companies), a review of the literature and other published 
sources, and on discussions with various individuals and companies. 



SCREENING OF WORLD WIDE OPERATIONS 



wp/3763-15/sect5.rep/a 

Outside of Ontario, the major metal mining provinces are British Columbia and Quebec. The Manitoba 
operations of INCO and Hudson Bay Mining and Smelting are also of note 

There are few operations in the Maritimes, apart from those of the Iron Ore Company of Canada, in 
l_abrador and the Noranda/Brunswick Mining operations In New Brunswick. Alberta has no metal mines. 
Saskatchewan has a small number of operations, of which those of the greatest interest to this study are 
the uranium producers at Key Lake and Quff Lake. 

in preparing the inventory of selected Canadian operations, emphasis was placed on providing a 
comprehensive representation of the more advanced wastewater control technologies employed 
throughout the country. Some emphasis was also placed on providing a measure of geographic 
representation to illustrate the distribution of technology use 

Appendix A lists all of the Canadian mines and mills In operation during 1990. 

5.3 UNITED STATES PROCESSING PLANTS 

A complete listing of operating US mines, mills and smelters is published in the American Mines 
Handbook (1990 - most recent edition). From the listings provided. Kilborn and EAG contacted all base 
metal (14), smelter/refinery (14), and iron (7) operations. Contacts were made by telephone and 
through use of a questionnaire. In many Instances, the questionnaire was filled out over the telephone. 

Contacting all operations in this manner was possible because the total number of operations was small. 
Response in nearly all cases was positive, although a few operators declined to provide information. 

A comparatively large portion of operators contacted were practising "zero volume discharge' because of 
favourable climatic conditions. This was particularly true of copper producers, which are located 
primarily in the arid southwest, and smelter/refinery operations. 

The gold sector has a much larger number of producers, which made it impractical to contact all 
operations. More importantly, US EPA regulations (Code of Federal Regulations-40-Part 440 1989. 
Development Document for Effluent Limitations, Guidelines and Standards for the Ore Mining and 
Dressing Point Source Category 1982). require that cyanide leaching operations (either in-plant or heap- 
leach) exercise 'zero volume discharge' of effluent, except In cases where a net annual surplus of 
precipitation (over evaporation) makes 'zero volume discharge' impractical (see Section 4.3). The vast 
majority of gold producers in the US are located in net evaporation (arid) zones of the western United 

5 - 2 SCREENING OF WORLD WIDE OPERATIONS 



wp/3763- 15/scct3.rep/a 

States, particulary in Nevada, Colorado, California and Montana. Mines and mills located in the 'net 
evaporation" clinnatic zones were not contacted. 

Gold mines located in areas of potential 'net precipitation' were contacted by telephone, to determine 
whether or not they practised zero volume discharge, and if so, what effluent treatment practices and 
monrtoring standards were employed. 

Approximately 20-25 mines/mills were considered as being potentially located In 'net precipitation' 
areas, primarily in the mountainous regions of the western United States (e.g. Idaho, Washington. 
Colorado, etc.). Contact with these operations determined that all but two operations were able to 
achieve zero discharge, principally because they happened to be located in rain shadow areas. The two 
exceptions were the Homestake Mine in South Dakota, and the Ropes Gold Mine in Michigan (see 
Section 6.1.3). 

Silver operations in the United States, with few exceptions, were not contacted directly as it was 
determined that nearly all prinnary producers are located in the arid southwest, and that secondary 
producers are included within gold and base metal producers. Also, wastewater control technologies 
employed in the production of sHver. are not different from those employed by base metal and gold 
operations. 

On final analyses, there are very few US operations (mostly lead/zinc producers) which discharge 
effluent wastewaters to surface waters. This Is because most producers are located in 'net evaporation' 
areas, or because compensation for small excesses in net precipitation can be achieved by a 
combination of wastewater retained in tailings voids and by extensive use of recycle. Also, where 
excess mine water is produced, beyond that which can be used in milling operations, mine water is 
normally kept separate from mill wastewater. Such wastewaters are then treated by primary and 
secondary settling, without regard for process chemicals. 

Further, among those base metals producers which do discharge to surface waters, the majority are 
located in calcareous (limestone/dolomite) geological settings. In such settings, effective wastewater 
treatment can generally be achieved by primary and secondary settling, without the use of chemical 
precipitating agents. The major exceptions to this generalization are the Alaska lead/zinc producers 
(Red Dog and Greens Creek) which process massive sulphides. Wastewater treatment practices used 
here are similar to those used at many Canadian operations. 



SCREENING OF WORLD WIDE OPERATIONS 5 - 3 



«p/3763-lb/sect5.tep/a 

For the above reasons, it was determined that comparatively few mine/mill wastewater treatment 
systems in the United States relate to Ontario operations. Alasl<an operations being among the ma)or 
exceptions. Where valid comparisons can be made, these were included in the mine/mill inventory (see 

Section 6) 

Site visits to United States operations were not undertaken, since, where applicable, employed 
wastewater treatment technologies are not appreciably different from those used in Ontario, or in the rest 
of Canada 

5.4 EUROPEAN PROCESSING PLANTS 

European contacts were restricted to 'western' Europe, as distinct from 'eastern' Europe and the 
European portion of the Soviet Union. Contacts with eastern Europe and the Soviet Union were not 
attempted, principally because there is little evidence to suggest that employed pollution control 
technologies represent an advancement over Best Available Technologies used in North America and 
western Europe. Also, obtaining data from eastern Europe, and especially from the Soviet Union, is 
difficult 

Within western Europe, emphasis was placed on the more northern countries of Sweden, Finland, 
Norway, Germany, France, Great Britain, and Belgium. These areas are broadly similar to Ontario in 
terms of technological development, environmental awareness, and climate. 

In southern Europe, enquiries made to Asturiana de Zinc S.A.(Spaln), and with AGIP Minière (Italy), 
indicated that pollution control technologies of greater sophistication than those used elsewhere in 
Europe and/or North America, were not being used. Also, the climate of most of Italy and Spain is 
comparatively dry, giving rise to conditions of net annual evaporation. 

Initial contacts with northwestern European countries were made through their respective embassies. A 
form letter was prepared to outline the nature of the study, and to request the names and addresses of 
key contacts in industry, government, and professional organizations. From the information provided, as 
well as from contacts already known to Kilborn and EAG. a telephone/FAX series of contacts were made 
with key companies, and in some cases, regulatory authorities. A desire to visit plants using innovative 
wastewater control technologies was expressed. 



SCREENING OF WORLD WIDE OPERATIONS 



wp/3/03 I'j/occlS rop/0 

5.5 AUSTRALIAN AND NEW ZEALAND OPERATIONS 

Australian and New Zealand operations have, with few exceptions, limited relevance to the Ontario 
setting. In Australia most mining operations are located in arid zones. In New Zealand, the recently 
emerging metal mining industry comprises three new gold mines and there is only a limited history of 
effluent treatment results. 

Certain areas of Australia (notably the south east including Tasmania) and New Zealand have a wet, 
temperate climate and also host a number of base metal and gold mining properties. Gold operations in 
New Zealand particularly are all recently commissioned or In construction phases. Treatment 
technologies being applied do however reflect currently formulated regulatory limits and best available 
methods. 



SCREENING OF WORLD WIDE OPERATIONS 5 - 5 



wp/3763-15Aabotco 



SECTION 6 
INVENTORY OF SELECTED PLANT OPERATIONS 



v*p/3763-15/9ect6.rep/« 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

6 INVENTORY OF SELECTED PLANT OPERATIONS 

6.1 GOLD MINES AND MILLS 

6.1.1 Ontario Processing Plants 

The processing of gold ores in Ontario generally involves a combination of: gravity concentration, 
cyanidation, flotation concentration, and carbon-in-pulp (CIP) or carbon-ln-leach (OIL) recovery. Gravity 
separation alone is not practised in Ontario. Flotation concentration alone was formerly practised at the 
Aquarius and Goldlund Mines which are now closed. Roasting and more recently pressure oxidation are 
employed to liberate gold from arsenopyrite containing ores of the Red Lake area. 

Gold mills which produce only a flotation concentrate typically have effluents which are low in heavy 
metals, provided that adequate effluent retention time is available in tailings ponds for solids separation. 
Wastewater treatment systems for such effluents are therefore more typical of those applicable to low 
sulphide base metal operations. Where arsenic is present in significant quantities, additional treatment 
for this contaminant may be required. At the Red Lake operation of Placer Dome Inc. an ore containing 
high levels of arsenopyrite is being processed using flotation - pressure oxidation and cyanidation. 
Effluent quality data and treatment requirements (if any) are not yet available for this newly 
commissioned plant. 

All active gold mines in Ontario use cyanidation, with gold recovery by either carbon-in-pulp. carbon-in- 
leach, or filtration-zinc precipitation (Merrill-Crowe). Wastewater treatment processes include: natural 
degradation, the INCO SC^-Air process, hydrogen peroxide, and the Hemlo Gold process. In all 
instances where chemical treatment is used, natural degradation is used as a pre-, and sometimes post, 
treatment. In the Hemlo gold camp, where arsenic, antimony and molybdenum are present, ferric ion 
(as chloride or sulphate) precipitation is incorporated into the effluent treatment system. Arsenic in the 
Red Lake operations has historically been recovered as a product during roasting or in flotation 
concentration with no specific effluent treatment being applied. 

6.1.2 Canadian Processing Plants Outside Ontario 

There are currently about 30-35 operating gold mines/processing plants in Canada, outside Ontario, with 
the majority of these located in Quebec. More limited operations occur in British Columbia, 

INVENTORY OF SELECTED PLANT OPERATIONS 6 - 1 



ivp/3763-15/sect6. rep/a 

Saskatchewan, the Northwest Territories and the Maritimes. None ot the Manitoba gold mines are 
currently operating. 

By and large, wastewater treatment practises used elsewhere In Canada, are not appreciably different 
from those used in Ontario. The majority of operations rely on natural degradation, frequently 
augmented by chemical treatment, principally the INCO SOj-Air system, or hydrogen peroxide. Where 
arsenic is present, ferric Ion precipitation Is typically used as an add-on treatment component. 

A notable exception to the above generalization, which differs from current practices in Ontario. Is use of 
the INCO SOj-Air process for treating effluent slurry, as opposed to the treatment of waste barren, or 
tailings pond effluent. There are currently five operating gold mills in Canada, outside Ontario, where 
this practice occurs (INCO Exploration and Technical Services 1991). Three of these operations (Les 
Mines Casa Berardi. East Malartic and Kiena) are located in Quebec, the remaining operations are 
located in British Columbia (Westmin/Premier and Golden Bear). In Newfoundland the Hope Brook 
Mine (recently placed in standby mode) also used INCO SC^-Air treatment of slurry, as did Equity Silver 
(British Columbia - silver/gold production). 

Treatment of slurry is normally attractive for plants employing CIP or CIL extraction, where the available 
topography does not lend itself to the creation of suitably sized tailings ponds, or where tailings pond(s) 
are far removed from the plant site. Othenwise, obtaining at least some measure of cyanide and heavy 
metal reduction through natural degradation is desirable, followed by chemical treatment of the clarified 
effluent. 

The S02-Air treatment system, and/or its derivatives, generally provide the only demonstrated effective 
chemical treatment system for the destruction of cyanide in slurries, proven effective in Canada at the 
operations level. Other systems, such as those using alkaline chlorination and hydrogen peroxide, have 
been variously used at selected Canadian operations (for slurry treatment), but thus far have met with 
limited success. The Vitrokele^^ method of cyanide recovery from slurry has been tested at the pilot 
plant level, at Hope Brook, Newfoundland, as well as at Bell Creek in Ontario, and shows promise, but 
for the purposes of this review must be regarded as unproven at the operations level. 

In addition to the above, two operations in Saskatchewan are of interest. These are the Jolu Gold Mine 
and Cameco's Jasper Operation. These two operations utilize effluent percolation systems through 
muskeg as part of their respective treatment systems, to assist in the removal of heavy metals. At the 
Jasper operation, percolation through muskeg is used as an add-on to conventional natural degradation. 

6 - 2 INVENTORY OF SELECTED PLANT OPERATIONS 



«p/3?63 15/secI6.rcp/a 

A similar, though less elaborate system, was used at Canamax's Kremzar operation (currently closed 
down), in Ontario. 

The Jolu Mine utilizes a more complex effluent treatment arrangement involving natural degradation, 
followed by hydrogen peroxide treatment for the destruction of cyanide, and ferric ion precipitation for 
the removal of arsenic. These are In turn followed by percolation through muskeg as a final 
filtering/polishing step. 

Another system of some interest is that utilized by the Lupin Mine, in the Northwest Territories. This 
operation uses a combination of natural degradation and ferric ion precipitation (for arsenic removal), in 
a batch discharge treatment system. The tailings pond area is quite large (approximately 8 knf ) and is 
divided into two principle sections, with various subcells for tailings solids storage. 

In basic principle, the system is operated much like American Barrick's Holt-McDermott site, in Ontario, 
i.e. collected effluent is aged in a primary tailings pond, before being seasonally batch discharged to a 
large polishing pond for further long-term aging in the absence of fresh tailings input. Final discharge is 
seasonal. The major difference between the two operations, other than tailings pond configuration, is 
the use of ferric ion precipitation at the Lupin Mine. 

Finally, Doyon Mine, in Quebec, is of interest because of its use of a high density sludge plant for heavy 
metal removal. This situation, while not unique, is unusual for a gold mine, being more typical of a base 
metal operations. The requirement for a high density sludge plant at Doyon Mine is necessitated by the 
acid generating nature and base metal content of the tailings and waste rock. 

6.1.3 United States Processing Plants 

US milling operations using cyanide are subject to the 'zero volume discharge' criterion, following from 
the US EPA 1982 Development Document for Proposed Effluent Limitations and Guidelines - Ore Mining 
and Dressing, and the Code of Federal Regulations. Part 440, 1 989. 

Zero volume discharge is attainable throughout the greater part of the continental United States, in areas 
where gold mining occurs, because of favourable climatic conditions (ie. where annual evaporation 
exceeds precipitation). Also, where annual precipitation slightly exceeds annual evaporation, zero 
volume discharge may still be possible because of seepage losses to ground water, and because some 
water is retained In tailings voids. Seepage losses are regarded as a concem in many states, and as a 



INVENTORY OF SELECTED PLANT OPERATIONS 6 - 3 



wp/3763-15/sect6.rcp/a 

result, new tailings facilities may have to incorporate liners into their design, for example the Ridgeway 
Gold Mine in South Carolina, and the Mineral Hill Mine located near the Montana-Wyoming border. 

Where zero volume discharge cannot be attained, because of climatic conditions (le. net precipitation 
areas), discharge js permissible according to US EPA regulations. However, at the time the 1982 
Development Document was written (1979-1982), limits for cyanide concentrations were not provided, 
nor have any such limits been developed since that time (Baldwin Jarrett, US EPA and author of the 
1982 Development Document, pers. comm). Limits were not set In 1982 because cyanide treatment 
technologies, other than natural degradation, were not In common use at that time, and therefore could 
not be properly evaluated. 

Where discharge from gold mills is theoretically permissible, because of net precipitation, two options 
are open. Either the state can set its own limits, or the state can require that flotation be used as the 
sole means of gold recovery, with further processing of the concentrate to be undertaken elsewhere. We 
are aware of one instance where cyanidation has not been permitted (the Jamestown Mine in California), 
and where a flotation concentrate is produced. The reason for preclusion of cyanidation, in this 
instance, has been to protect ground water resources, rather than to restrict surface water discharge. 

The only active, or recently active, US gold mines, to our knowledge, to use cyanidation in a situation 
requiring surface water discharge (and therefore requiring limits on cyanide to be set by a state 
government) are the Homestake Mine in South Dakota, and the Ropes Mine in Michigan. Also in the 
early 1980's the Grey Eagle Mine was operated in N. California on the site of a previous copper mine. 
Initially alkaline chlorination was employed for cyanide destruction, followed later by peroxide treatment 
due to the high levels of copper-cyanide complex. Treatment of seepage from the tailings tjasin 
continues although the mine has ceased to operate. Current treatment utilizes sodium hydroxide for 
copper precipitation. 

The Homestake mine/mill uses a unique method of biological effluent treatment which acts effectively as 
a banery of rotating biological contactors (RBC's). A dilute solution of mine water and mill effluent is 
treated. Mine water temperature is sufficiently elevated to allow active, open air, biological treatment 
year-round. Further treatment details are described in Section 3.1. The required cyanide concentration 
in the final effluent, measured as total cyanide is 0.33 mg/L 

The Ropes mine/mill opened In 1985 and operated at 2200 tons/day until 1990. The milling process 
employed cyanidation followed by Merill Crowe gold recovery. Wastewater treatment at the Ropes 

6 - 4 INVENTORY OF SELECTED PLANT OPERATIONS 



wp/3763-15/5ect6.rep/a 

mine/mill consisted of alkaline chlorination of the waste barren stream (switchied to hydrogen peroxide 
treatment in 1988), with treated waste t>arren and repulped filtercake tjeing discharged to an open pit, 
formerly part of an iron mine Open pit waters seeped through a permeable berm, to a wetland, and 
passed from there to the receivitig water. 

The state of Michigan did not set limits on cyanide concentrations, during operation, but required site 
monitoring. Copper and nickel limits were set at 0.05 and 0.6 mg/L, respectively. These levels were not 
met. in order to resume operation, the state has indicated that the concentration of cyanide amenable 
to chlorination (which excludes ferri- and fen-o-cyanide species), must be reduced to 0.004 mg/L in the 
final effluent. Laboratory test work has indicated that this level cannot be achieved. Negotiations are 
continuing between the company and the state, but are not progressing, partly because the mine is 
uneconomic at today's gold prices. 

In addition to the above, and irrespective of the ability to operate without discharge, several gold mills 
and heap leaching operations in the continental US use some form of cyanide treatment, other than 
natural degradation, to reduce cyanide levels in their tailings ponds. This measure is required to protect 
wildlife, which are attracted to ponds, particularly in arid climates, such as Nevada. Cyanide limits are 
set as those which are "non-lethal" to wildlife, and seem to range from about 5-50 mg/L, as total 
cyanide. Hydrogen peroxide, chlorination, and INCO's SO^-Air process, are employed for this purpose. 
Ferrous sulphate treatment of mill tailings has been used briefly in at least one case. In the case of 
INCO's SC^-Air process, both clear solution and slurries are treated. 

To the extent that the US EPA's BAT requirement of zero volume discharge' is not applicable to the 
Ontario setting (see Section 4), and since there are no currently operating gold mines/mills In the United 
States (other than Homestake which is a unique operation) which employ cyanidation and which 
discharge to surface waters, US BAT technologies (excluding those related to heavy metal reduction) are 
considered herein to have no relevance to, and are therefore not applicable to, the Ontario gold mining 
sector. 

6.1.4 European Processing Plants 

Based on information provided by various government and industry representatives, there appear to be 
no active gold mines/mills, in northwestern Europe (ie. Scandinavia, Germany, the Netherlands, and 
Great Britain). There are, however, two possible mines which could open in the near future, one in each 
of Sweden and Nonway (Niclas Svenningsen - Swedish Environmental Protection Agency; Sir! Sorteberg 



INVENTORY OF SELECTED PLANT OPERATIONS 



wp/3763-15/sect6.rep/a 

- Norway State Pollution Control Authority, pers. comm.). Tiie choice of wastewater treatment 
operations for these two properties remain to be determined 

Elsewhere in Europe, and excluding southern and eastern Europe and the Soviet Union, there are very 
few gold operations, other than possibly those which process concentrates. France appears to be the 
largest producer at 4.2 tonnes in 1990. We are only aware of one operating gold mine in France, the 
Salsigne Mine. Effluent treatment at this mine reportedly consists of ferrous sulphate and hydrogen 
peroxide addition. The effluent contains arsenic, and overall environmental perfomnance is unknown to 
the study group. 

From the above, gold mining operations In Europe are too limited, to have relevance to the investigation 
of BAT technologies potentially applicable to Ontario. 

6.1.5 Australian and New Zealand Operations 

Australia is a major gold producer. However, the greater part of Australia is a net evaporation area, and 
to our knowledge, with a single exception, gold mining is confined to this area. The exception is the 
Goiconda Mine, in Tasmania which used the AVR process for cyanide recovery. The mill commenced 
operation in 1985, but is currently shutdown. Elsewhere in Australia, achievement of zero volume 
effluent discharge is the norm, because of the dry climate. 

Gold mining in New Zealand is a recent development, with the first mill, Waihi Gold becoming 
operational in 1989. The two current operations in New Zealand use a wastewater treatment train 
consisting of: natural degradation, hydrogen peroxide destruction, mechanical settling with flocculation 
and mechanical (active sand bed) filtration This is the only instance, of which we are aware, where 
active sand filtration is used to treat gold milling wastewaters. 

6.2 BASE METAL MINES/milLLS/SIVIELTERS 
6.2.1 Ontario Processing Plants 

While a number of base metal mines currently operate in Ontario, the use of central processing facilities 
reduces the number of actual concentrators. A number of the concentration facilities are integrated 
with smelters. Further, much concentrate is shipped out of the province to smelters elsewhere in 
Canada, to the U.S. or offshore. A total of four primary smelter/refinery complexes are in use for base 
metal production in Ontario. In the case of INCO Ltd.'s Sudbury operations, wastewaters from several 
sites are all collected and treated at one central treatment plant (Copper Qiff treatment plant). There are 



6 . 6 INVENTORY OF SELECTED PLANT OPERATIONS 



wp/3763- 15/sect6.rep/a 

only ten treatment plants for base metal mill/smelter effluents (MISA Development Document. 1989) in 
the Province. In addition there are a number of stand-alone mines wfilch treat only mine water. 

At Falconbridge's Kidd Creek operation, and at N/linnova's Winston Lake operation, wastewater treatment 
consists of primary settling followed by lime addition, followed by secondary and tertiary settling. At the 
Falconbridge smelter, an engineered wetland complex is used for the secondary treatment of pre-limed 
effluent. 

At the Falconbridge Strathcona plant, tailings are discharged into a solids retention area on Moose Lake. 
Effluents percolate through a permeable solids retention dam and are initially treated in the 
lake. Discharge from the lake is controlled at the neutralization dam, where Moose L^ke decant is 
treated by lime addition. A 7% lime solution is mixed with the decant water at the flume and the treated 
effluent is polished in Lower Moose Lake. The pH of the decant water from Lower Moose Lake is 
adjusted (acidified) using CC^ injection prior to final discharge. 

INCO's Copper Cliff and Nolin Creek wastewater treatment plants both employ lime addition, polymer 
addition and clarification to treat effluents. The Copper Cliff facility treats wastewater from the tailings 
pond and the smelter. Raw wastewater is treated by lime addition in the raw water well, followed by the 
addition of polymer. This solution is pumped to two large diameter clarifiers. Clarifier overflow is 
discharged to Copper Cliff Creek, while the low density sludge is returned to the tailings pond. The 
Nolin Creek wastewater treatment plant treats site drainage from the Clarabelle Mill, limited slag dump 
drainage and seepage from the Copper Cliff plant. A single clarifier is used. Clarifier overflow is 
discharged to Nolin Creek and the low density sludge is returned to the tailings pond. 

INCO's Port Colbourne refinery uses hydroxide (lime) precipitation and flocculant-aided merchant settling 
for waste water treatment. 

Finally, at Noranda's Geco and Mattabi mills, high density sludge treatment plants employing lime 
neutralization are used to remove heavy metals. 

6.2.2 Canadian Processing Plants Outside Ontario 

There are nine active primary lead/zinc, 23 primary copper, and four primary nickel mines/mills in 
Canada, outside of Ontario, as well as nine base metal smelter/refinery complexes (Canadian Mines 
Handbook 1991-92). The term primary is in reference to the principal metal recovered. In addition, 



INVENTORY OF SELECTED PLANT OPERATIONS 



WP/37G3 1 5/sect6.rep/a 

there are a number of temporarily suspended and/or discontinued base metal operations, which are 
currently treating site area wastewaters, primarily to control acid mine drainage. 

Wastewater treatment systems vary according to circumstances (ie. ore type, geographic setting, plant 
age, etc.). and can be arranged into the following categories: 

• zero volume discharge (British Columbia rain shadow area) 

• tailings ponds alone 

. under water tailings disposal 

• lime neutralization 

• lime neutralization with mecfianical settling 

. lime neutralization followed by active sand bed filtration 

• lime neutralization with sulphide precipitation, sand filtration and pH adjustment (one plant) 

Gibraltar Mines Ltd.'s operation near McLeese. British Columbia (240 km northwest of Kamloops), is one 
of the few Canadian base metal operations to practice 'zero volume discharge'. This operation, like 
some in the northwestern United States, is located in a rain shadow area, and is therefore able, with high 
wastewater recycle (92%) and water lost to tailings voids, to achieve 'zero volume discharge'. 

Underwater disposal of massive sulphide tailings, in the absence of any other form of wastewater 
treatment, is practised by: Cominco's Polaris Mine in the Northwest Territories, BHP-Utah's Island 
Copper Mine (deep sea disposal), and by Hudson Bay Mining and Smelting at their Snow Lake 
copper/zinc concentrator in Manitoba. This practice is working well at these operations. Ultimate mine 
closure is also facilitated by undenwater disposal, which serves to prevent and/or restrict oxidation of 
high sulphide tailings. 

Simple lime neutralization, integrated with use of primary and secondary settling ponds, is used at a 
number of Canadian base metal operations, such as Hudson Bay's Flin Flon concentrator/smelter 
complex, in northern Manitotia, and in most New Brunswick and Quebec plants. 

In many newer facilities, or where adequately sized retention ponds cannot be provided assistance in the 
form of, mechanical settling devices (often reactor /clarifiers) is frequently included as part of the 
treatment system. Many such systems employ sludge return (high density sludge plants) to improve 
overall efficiency, and to minimize sludge storage requirements. High density sludge plants are 
commonly used by Noranda, Cominco and other Canadian operators, and are particularly favoured for 

6 - 8 INVENTORY OF SELECTED PLANT OPERATIONS 



wp/376î-15/5ect6.rep/a 

post-production, add mine drainage control where co-deposition with the tailings solids Is not a disposal 
option. 

The only Canadian base metal plant currently using mechanical effluent filtration, to our knowledge, is 
Minnova's Samatosum Mill, in British Columbia. The Sannatosum operation, after removal of solids in a 
conventional tailings pond , treats the decant solution using two-stage precipitation of base metals with 
lime and sodium sulphide. The sodium sulphide addition controls the level of residual cadmium in the 
solution. Precipitate Is removed by active sand bed filtration. A final pH adjustment is made with 
sulphuric acid to ensure a discharge solution value of 6.5-9.0 pH units prior to entering the receiving 
watercourse. 

6.2.3 United States Processing Plants 

As determined from the latest version of the American K/lines Handbook (1990), there are thirteen 
primary lead/2inc, thirteen primary copper, and one primary nickel producing operations in the United 
States. These include mines, concentrators, and, in the case of copper, in-situ leach operations. 

In addition, there are seven primary lead/zinc smelters, and seven primary copper smelters. The single 
nickel operation, Gienbrook Nickel - Oregon, is also a smelting facility. 

Fully twelve of the thirteen primary copper producers are located in arid portions of the United States (ie. 
Arizona, New Mexico, Utah and Montana). All of these operations are able to operate with 'zero volume 
discharge' because of favourable climate (ie. annual evaporative losses exceed precipitation inputs to 
tailings impoundments). 

The single exception is the Coeur Mine/Mill in Idaho operated by Asarco Inc. This mine/mill operates in 
conjunction with the Asarco/Callahan Galena Unit, with both operations using a common tailings facility. 
This common tailings facility is a simple pond, which discharges mainly to groundwater, and 
occasionally to surface water. There is no chemical or other treatment of mill tailings, other than primary 
settling. Ore types, at both operations, are calcareous with low sulphides. Hence there is no difficulty 
reaching US EPA required effluent limits. 

Primary lead/zinc operations in the United States are concentrated in the Missouri Lead Belt, Tennessee 
(zinc), and more recently in Alaska (the Red Dog and Greens Creek Mines). There are also single 
operations in each of Colorado (the Leadville Mine), New York state (NJZ Mines), and Idaho (Galena 
Unit-see above). 

INVENTORY OF SELECTED PLANT OPERATIONS 6 - 9 



»/p/3763-15/sect6.rep/a 

The Missouri Lead Belt is founded on zones ot dolomitic limestone, with minor galena and sphalerite. Mill 
tailings are consequently basic, and therefore easy to manage. Tailings/wastewater treatment methods 
are restricted to primary and secondary settling, followed in one instance (Sweetwater) with an 
engineered wetland. At the Magmont operation, a flocculant is used to treat the thicl<ener overflow, prior 
to discharge to tailings. The Sweetwater operation is currently facing a reduction in acceptable lead 
concentrations in its final effluent from the US EPA limit of 0.3 mg/L to 0.054 mg/L The latter limit is 
the average of concentrations achieved over the past 1 8 months. 

At Asarco's recently developed West Fork Unit (commissioned In 1987), the company has been able to 
achieve 'zero volume discharge" despite a slight net excess in annual precipitation over evaporation. 
Zero volume discharge, in this case, is attainable because of the use of extensive recycle. In 
combination with the water holding capacity of tailings voids. The West Fork tailings basin is lined by a 
minimum three foot thick clay liner, primarily comprised of naturally occurring, in-place materials. 

Jersey Miniere's Elmwood/Gordonville orebody, in Tennessee, is also located in a calcareous 
(limestone) formation. Treatment of mill tailings and wastewater is restricted to primary and secondary 
settling, without the use lime or other settlement/flocculating aids. 

Zinc Corporation of America's NJZ zinc mine in New York utilizes lime as a settling aid, added in the mill 
tailings pumpbox prior to discharge to the tailings pond. Ore types here are also predominantly 
calcareous. 

Of greater interest and relevance to the Ontario setting, are the three massive sulphide operations, Red 
Dog and Greens Creek in Alaska, and the Leadville Unit in Colorado. The Leadville operation is one of 
the very few in the United States in which ammonia is an effluent control parameter (limit 4.5 mg/L as 
total ammonia) specified by local authorities. The Leadville operation uses in-plant lime treatment of the 
mill slurry, sometimes in combination with flocculant addition, followed by primary and secondary 
settling, and lastly by pH adjustment. Surface aerators are used on the primary tailings pond, during 
winter, to facilitate ammonia loss through volatilization. Effluent discharge standards deviate only slightly 
from standard US EPA limits (Table 4-2). 

More sophisticated wastewater treatment methods are used at the two Alaskan operations, both 
commissioned since 1989. The Red Dog Mine, operated by Cominco Alaska, utilizes a multi-stage high 
density lime sludge reactor/clarifier plant, similar to those used by Cominco, Noranda and Hudson Bay 
at some of their Canadian operations. 

6-10 INVENTORY OF SELECTED PLANT OPERATIONS 



wp/3/63-15/5ect6.rep/B 

Kennecott's Greens Creek operation uses a more novel approach to effluent treatment, partJy because of 
the very high run-off conditions. Final effluent discharge is to the Pacific Ocean. The mill tailings slurry 
is filtered (pressure filter) to produce a partially dry cake, which is then trucked to the tailings 
containment basin. The filtrate Is first treated with hydrogen peroxide to remove cyanide (used In the 
flotation process), followed by heavy metal precipitation using lime and a polymer flocculant in a 
reactor/darifier. The resulting effluent is discharged to the prinnary settling pond, along with mine water. 
Ume and flocculant are again added at the transition from the primary to the secondary settling pond. 

The Greens Creek operation is one of the few United States operations where toxicity testing Is required, 
and the only one which we are aware of where passing the toxicity test is a compliance requirement. 
Zero statistical mortality is permitted at a 50:1 dilution of final effluent. Trout are used as the test 
organism. The high dilution testing ratio is permitted because effluent Is discharged directly to the 
ocean. 

The Glenbrook (formerly M.A. Hanna) nickel mine, in Oregon, although having wastewater discharge, is 
not directly applicable to the Ontario setting. At this site, latérite ferro-nickel ores are mined at surface, 
without the use of explosives, and are fed directly to a pyrometallurgical smelter. Wastewater, primarily 
derived from the granulation of slag, is treated by primary and secondary settling, without the use of 
chemicals. 

Regarding the operation of smelters, all primary copper smelters in the United States achieve 'zero 
volume discharge', as do most of the lead /zinc smelters. The only exceptions are Zinc Corporation of 
America's Oklahoma zinc smelter, and Asarco's Glover smelter in Missouri. Zinc Corporation of 
America's Oklahoma smelter disposes of its wastewater by deep (underground) injection into fractured 
limestone formations. This disposal method is not suited to the Ontario mining environment. 

Asarco's Glover lead smelter is unique in the United States in its use of sulphide precipitation. Effluent 
treatment at this operation utilizes: lime precipitation, followed by sulphide precipitation, followed by 
flocculation in a reactor/darifier. followed by filtering (filter press) with Gortex fabric. The final treated 
effluent is directed to a settling pond. 

6.2.4 European Processing Plants 

Base metal mining in many areas of Europe, outside of the Soviet Union and eastern Europe, has 
declined over the years to the point where a majority of ore deposits are severely depleted, and/or 
mined out. Scandinavia, Finland, Portugal/Spain and Ireland remain strong producers. 

INVENTORY OF SELECTED PLANT OPERATIONS 6-11 



wp/3763-15/sect6.rep/a 

In the U.K. there is only one remaining non-ferrous metal mine in operation, a small tin mine in the 
Cornwall area (Mr. G. Ljeun, Carnon Consolidated Ltd.). The last active metal mine in what was formerly 
West Germany is expected to close shortly and mining in Italy is confined to lead/zinc operations on 
Sardinia (Mr. V. Baldini. AGIP Minière). 

In Norway and Finland, base metal mining still provides a significant, though declining resource. Finland, 
for example, has nine operating metal mines, six of which are expected to close in the next two-three 
years. France still produces some lead/zinc ores, but production is declining. The Netherlands and 
Denmark have no active metal mines. The largest lead/zinc mine in Europe is the Tara Mine in Ireland. 

Deficits in ore production, in most European countries, are compensated for by the processing of base 
metal concentrates derived from off-shore sources. This Is particularly true of Germany, Belgium, 
Finland and the UK. These smelters and refineries treat a wide variety of feed materials containing 
impurities such as arsenic, cadmium and thallium. Custom smelting operations are able, to some 
degree, pass along waste water treatment charges to concentrate producers in the form of treatment 
charges and penalties for smelting and refining. Smelting wastewaters tend to be relatively 
contaminated but volumes are comparatively low. For these reasons, wastewater treatment practices 
associated with smelters and refineries may be more elaborate, than those used at mines and mills 

Base metal mines in Europe (excluding selected smelters and refineries in some of the more 
technologically progressive countries) treat mine/mill wastewater through a combination of hydroxide 
precipitation and settling ponds, as in Canada. 

The only exceptions to this generalization appear to be the Laisvall and Boliden area mines, and the 
Ronnskar smelter, operated by Boliden Mineral AB in Sweden. At the Laisvall Mine, wastewaters are 
treated with a combination of: sulphide precipitation, followed by flocculation and sand filtration. At the 
Boliden area mines, mine effluents are treated by a combination of: lime precipitation, flocculation, 
lamella clarifiers, and sand filtration. Treatment of smelter effluents at the Ronnskar operation includes 
sodium sulphide and lime precipitation followed by precipitate dewatering (see following details of site 
visit). 

The most advanced (state-of-the-art) wastewater treatment technologies identified at stand-alone 
smelters and refineries are those technologies employed in (West) Germany. Preussag A.G. operates a 
lead/zinc smelter in Nordenham/Bremen and a specialty metals refinery in Achtfelt. Both operations use 
a multistage sulphide/hydroxide/ferric ion precipitation process with mechanical settling which Is 

6-12 INVENTORY OF SELECTED PU^NT OPERATIONS 



»vi»/3?6J- 1 b/occ«nop/B 

followed by styrofoam bead filtration (Dr. K. Roennefahrt. pers corrm. and site visit). Norddeutsche 
Afflnerie. A.G.. Hamburg, operates a multistage ferric ton/hydroxide/ferric hydroxide 
preclpitatlon/flocculation process, followed by sand filtration (details of site visit are provided below). 

In contrast, and more representative of typical smelter effluent treatment, the Métallurgie Hoboken- 
Overpelt refinery, in Antwerp, Belgium, treats wastewater with a combination of lime and ferric Ion 
precipitation, using reactor-clarifiers for mechanical settling. Sludges are de-watered in filter presses and 
returned to the process or disposed in landfill. 

Visits were conducted to t»ase metal smelters and mining operations in Sweden and Germany, where 
similar levels and styles of effluent treatment are practised. 

In Sweden, operations of the Boliden Mineral AB were visited and details obtained: 

a) The Ronnskar copper-lead smelter operation is located on the shore of the Gulf 
of Bothnia. Effluent requiring treatment comprises process effluent and yard 
drainage/stonnwater. The two streams are combined in a settling basin to 
remove solids prior to chemical treatment at an average rate of 125 rrf /h. 
Typical metal concentrations in the combined stream are arsenic 100 mg/L, zinc 
250 mg/L, lead 50 mg/L and copper 60 mg/L. at a typical pH of 2-3. 

First stage treatment consists of controlled sodium hydroxide addition and sodium 
sulphide addition prior to reaction in three agitated tanks at a target pH value of 4.0. 
The treated solution is pumped to a thickener together with flocculant to remove the 
Cu-Pb containing precipitate. The sludge is dewatered by a centrifuge then recycled 
to either the copper smelter or to a sealed stockpile for later reclaim. 

Second stage treatment comprises additional reaction and pH adjustment with lime 
to a pH level of 12 for removal of arsenic and fluorine which is retained in a settling 
pond. Solution flows to a secondary pond where dilute waste acid from the smelter 
is added for adjustment of pH to 7.0 prior to marine discharge. 

The effluent treatment plant was constructed in 1977-8 and is a stand-alone 
operation with its own control room complete with computer control and monitoring. 
Influent and effluent streams are monitored by an on-stream analyzer reporting 

INVENTORY OF SELECTED PLANT OPERATIONS 6 - 13 



«p/3?63-i5/5ect6 rep/a 



values of arsenic, zinc and copper. Samples are taken automatically and analyzed 
as 24 hour composites. Final effluent solution is analyzed for the main elements of 
Cu, Zn, As plus Cd, Hg and Pb. 

Regulatory limits for discharge appear to be based on total loadings expressed as 
tonnes of metal per year. 

b) The Renstrom mine water treatment plant is similar to several others in the 
Boliden area. All employ conventional lime treatment followed by clarification In 
Lamella settlers and active sand bed filtration. A surge pond prior to treatment 
is employed to regulate flow to the treatment plant and final effluent is 
discharged via a second pond. Sludge from the ponds Is periodically removed 
by mechanical means and the sludge deposited In a neighbouring mill tailings 
pond. 

c) The Laisvall mine water treatment plant is located within the underground mine 
complex. This is an old mine producing lead and zinc with workings beneath a 
lake and a large inflow of water. Three categories of mine water are recognized 
and carefully segregated: 

1) Clean water which can be discharged to the lake, 

2) Water with low contamination levels is pumped to the mill for process use. 

3) Water requiring treatment is directed to a large surge sump. An 
average flow to treatment is 400 nf/h. 

The water treatment plant consists of a multi-cell bank of sand filters with newly installed 
computer control of sequencing and backwashing. Solution to be treated is pumped at a 
controlled rate to the cells after addition of sodium sulphide and flocculant solution. pH 
adjustment is not required. 

Metal sulphide precipitate trapped In the sand beds is removed periodically by backwashing, 
with the precipitate stream being directed to a surge sump. Sludge and water from the 
sump is pumped to other areas of the mine where it is combined with densifled mill tailings 
in backfilling operations. The treated water is pumped to surface for discharge to the 



INVENTORY OF SELECTED PLANT OPERATIONS 



wp/3763 -IS/secte-rep/a 

tailings pond Mill tailings slurry and decant Is treated by lime addition In the tailings pond 
to maintain the pH of the final effluent at 10 - 11.5. 

Treated effluent Is monitored principally for suspended solids, lead and pH. The objective 
level for TSS is 5 mg/L 

Water treatment plants associated with large smelter operations in Germany were visited and 
are described briefly: 

d) The lead-zinc smelter of fi^etaleurop Weser Zinl< is located in Nordenham on the 
banks of the Weser River. 

Site effluents are segregated into three categories and treated separately: 

• Domestic sewage is pumped to the local town treatment plant. 

• Stormwater is directed to a settling lagoon from which clear water 
is returned as process water make-ups. Settled sludge is 
periodically removed for treatment in the process water treatment 
plant. 

• Process effluent averaging 50rn?/h and with the pH at less than 2, 
is treated chemically to remove heavy metals and iron as a 
sludge. 

The treatment plant for process effluent comprises three stages of pH 
adjustment/reaction and subsequent thickening for recovered precipitate as a 
sludge. 

The first treatment stage employs addition of sodium sulphide, with the pH 
controlled in the range 2-4. In the second stage, the pH is adjusted to a range of 9- 
10 by sodium hydroxide addition, and sodium sulphide is added. Thickened sludge 
is recovered and dewatered by a filter press. The filter cake is hauled away by truck 
for disposal in a landfill site. 

In the third stage lime and a solution of ferric chloride/ferric sulphate is employed 
for final cleaning and removal of residual sulphides. The thickened sludge after 
filtration is recycled to the lead smelter sinter plant. 

INVENTORY OF SELECTED PLANT OPERATIONS 6-15 



//p/3763-15/secl6.rep/a 



Final effluent is cleaned by mechanical filtration using a bed of styrofoam beads and 
then discharged together with the main cooling water flow at 4000 nf /h to the 
Weser River. Off-gases from the reaction vessels are collected and wet scrubbed to 
remove hydrogen sulphide gas. 

Operation of the plant is monitored by a control room attached to the acid plant 
Contre) is maintained with analogue instrumentation due to the age of the plant 
(over ten years). 

Pretreatment of several streams is practised to smooth operations in the main 
treatment section. Certain solutions are air scrubbed to remove high levels of 
dissolved SO^. A zinc plant stream is pre-treated with sodium sulphide to remove 
mercury which is recovered separately for sale as HgS 

e) The copper smelter of Norddeutsche Affinerie Is located in the city of Hamburg 
on the t)anks of the river Elbe. This is a large industrial complex producing 
300 000 t/a of anode copper. 

Management of site effluent produces the following streams: 
Domestic sewage treated in municipal worl<s. 

• Two stormwater systems each 400 000 mP/a flowing to treatment plants. 

• Process effluent stated as 100 000 n? /a which is treated separately. 

The process effluent is treated to remove a range of elements resulting from the variety 
of concentrates being processed by the smelter. Current limits of concentration in the 
treated effluent are: 



Metal 


Limit 


mq/L 


Annual Average 
mq/L 


Cu 


0.5 




0.020 


Pb 


0.5 




0.007 


Ni 


0.5 




0.025 


Zn 


1.0 




0.020 


Cd 


0.2 




0.005 


Hg 


0.05 




0.0008 


As 


0.1 




0.026 


PH 


< 9 




7-8 


COD 


1 .5 kcg/t produced copper 


not provided 



6-16 INVENTORY OF SELECTED PLANT OPERATIONS 



wp/3763-1S/sect6.rep/a 

The plant employs sodium hydroxide for pH adjustment instead of lime, primarily to 
reduce ttte volume of sludge requiring disposal, currently 2 000 - 3 000 t/a. 

The collected process effluent solution, with a typical pH value of 2 is treated with 
sodium hydroxide and a solution of ferric chloride/ferric sulphate. The ferric 
arsenate precipitate is dewatered by thickening and pressure filtration prior to 
disposal. Treated solution is adjusted to a pH value of 7-7.5 with addition of sodium 
hydroxide, ferric sulphate and fiocculant. A second thickener recovers sludge which 
is recycled to the first thickener. The final solution is cleaned by a sand filter 
equipped with automatic backwash (backwash slurry is recycled to the second 
thickener) and the final treated solution is discharged together with spent cooling 
water to the river. 

6.2.5 Australian and New Zealand Processing Plants 

Australian base metal plants are located principally in arid zones and are therefore capable, or potentially 
capable, of achieving zero volume effluent discharge. In cases where mines are not located in arid 
zones, such as parts of Tasmania, effluent treatment methods used are not appreciably different from 
those currently used in Canada, the United States, and most of Europe. 

There are. to our knowledge, no active base metal mining operations in New Zealand. 

6.3 IRON MINES 

6.3.1 Ontario Processing Plants 

The only remaining iron ore producer in Ontario is Algoma's Wawa operation, which processes up to 
8 000 tons per day. This mine is unusual in that the ore mineral is siderite (iron carbonate), and 
production is from underground. Given that the ore body is carbonaceous, there is no potential for 
sulphide related heavy metal contamination. 

Wastewater treatment is limited to the use of settling ponds, for the removal of suspended solids from 
process wastewater, mine water and yard run-off. 

6.3.2 Canadian Processing Plants Outside Ontario 

Canadian operations outside of Ontario are comprised of the Iron Ore Company of Canada's Carol 
Division in Labrador; the Scully Mine, also in Labrador; and the Mount Wright Mine In Quebec. Total 
annual production of concentrates from the three operations is approximately 36 million tonnes. 

INVENTORY OF SELECTED PLANT OPERATIONS 6-17 



Wastewater treatment Is by primary and secondary settling with In-plant thickening prior to discharge to 
tailings 

6.3.3 United States Processing Plants 

Iron ore mining in the United States is concentrated in the iron ore belt of Michigan and Minnesota. Site 
data were obtained on four operations. Three of these operations rely solely on prinnary and secondary 
settling, for effluent treatment. Flocculants are used within the concentrator to assist in tailings 
thickening, prior to discharge from the mill. This latter measure reduces total effluent volumes, and is 
regarded as a best management practice, rather than a treatment process 

The Tilden Mine, in Michigan, appears to be the only iron ore mining operation in the United States 
which employs effluent treatment, other than primary and secondary settling. Concentrator discharges 
from this operation are directed to an engineered tailings basin seven miles from the mine site. Effluent 
from the primary tailings pond is subsequently directed to a reactor/clarifier, where it is treated with 
alum and two flocculating agents. 

6.3.4 European Processing Plants 

Investigations into European processing plants focused on Sweden. Nonway and France. Sweden (20 
million tonnes/year iron ore products) and France (8.7 million tonnes in 1990) are the major producers 
in western Europe. 

Iron ore mining in France is concentrated in the Lorraine area, where there are reportedly three major 
operations. Output from this region is declining. In each case, run-of-mine ore is trucked directly to the 
smelter without processing or concentrating 

In Sweden, as in most Canadian and United States mills, wastewater treatment consists of in-plant 
flocculation, to assist in thickening, prior to discharge to tailings. In most instances primary and 
secondary settling is practised. Monitored parameters consist of: suspended solids, turbidity. pH. 
conductivity, total nitrogen, chloride and sulphate. 

The two operations contacted in Nonway both discharge their tailings directly to fjords. Total solids 
concentrations in these discharges average from 15-21 percent, by weight. 



INVENTORY OF SELECTED PLANT OPERATIONS 



*Tj/3?63-15/iect6 rcp/« 

6.3.5 Australian and New Zealand Processing Plants 

Iron ore mines/processing plants In Australia, were not contacted, as there was little reason to suspect 
the use of technologies different from those described above for North America and western Europe, I.e. 
primary/secondary settling, occasionally aided by flocculating/precipitating agents. Most iron mining 
operations in Australia are carried out in the Pilbara region of Western Australia. 

There is no active iron mining in New Zealand, although production from an ilmenite deposit is being 
considered. 

6.4 URANIUM MINES/MILLS 

The world's major producers of uranium are the United States, Canada. Australia and South Africa. 

Current producers in the United States are all situated in net evaporation areas in the states of Arizona. 
Wyoming and Texas. These mines and mills operate with zero volume discharge of liquid effluent. 

In Australia the "three mines" policy is still in force. This is a federal ruling that allows only a maximum 
of three uranium mines to be in operation at any one time. The three mines that are currently operating 
are Ranger and Nabariek in the Northern Territory and the Roxby-Downs uranium-copper-gold operation 
in South Australia. These producers were contacted and were found to be practising zero volume 
discharge. 

In South Africa there are no primary producers of uranium. Uranium is produced as a by-product of 
gold production at mines which operate with zero volume discharge. 

Uranium production in Canada is confined to the provinces of Saskatchewan (Cluff Lake, Key Lake. 
Rabbit Lake) and Ontario (Elliot Lake). Production in Ontario continues to decline as a result of recent 
closures and production cutbacks in the Elliot Lake area. Canadian uranium producers are all net 
dischargers of effluent solution. 

Effluent treatment operations for control of conventional parameters of heavy metals, suspended solids, 
pH, etc. do not differ from those applied in the base metals sub-sector. Tailings ponds, lime 
neutralization, mechanical settling by clarifiers or sand filters and settling ponds are employed. 
Additional treatment features specific to the control of Radium 226 are integrated within these trains. For 
example, at Key Lake, Saskatchewan these additional features include barium chloride addition and sand 
filtration followed by ion exchange. All Canadian uranium plants use at least barium chloride addition for 

INVENTORY OF SELECTED PLANT OPERATIONS 6 - 19 



control of radionuclides. At the Rabbit i^ke plant In Saskatchewan, control of arsenic in the effluent is 
achieved by addition of ferric sulphate together with barium chloride In the radium precipitation stage. 

6.5 SILVER MINES/MILLS 

The United States, Mexico, Peru. Canada and Australia are the world's major silver producers. In 
Canada and Australia, silver is produced as a by-product of gold and base metal processing operations, 
for example, the Kidd Creek smelter/refinery in Ontario. Mining operations in the United States, where 
silver is the primary metal, occur mainly in the arid southwestern states. Exceptions are mills in Alaska 
(two), Idaho (two), Montana (two), and South Dakota (one). The mills in the latter states, occur In net 
evaporation zones, and therefore have zero volume discharge. The Alaskan operations are worked as 
placer deposits. Operations in Mexico and Peru are expected to be in net evaporation zones and 
wastewater control technologies in these two countries are generally not sophisticated. 

The Real del Monte silver operation in Pachuca, Mexico employs both flotation and cyanidation. The 
cyanide bleed stream (barren solution) is treated using AVR technology to recover cyanide internally In 
the processing unit. The treated solution is discharged together with the main flotation tailings stream to 
an impoundment area where a combination of evaporation and exfiltration to the surrounding farmland 
ensures no net discharge. 

Silver may be recovered either as a flotation concentrate (often in association with other metals), as a 
gravity concentrate, or through cyanidation. In the latter instance, treatment is normally confined to that 
involving very high grades, or to the treatment of concentrates. To the extent that the treatment of 
wastewaters from flotation mills and cyanidation mills are addressed elsewhere in this report (Sections 
6.1 and 6.2), separate treatment of silver plant wastewaters, in this section, is not required. 



INVENTORY OF SELECTED PLANT OPERATIONS 



I =1 



I II 
I *l 
I 'I 

li'i 



i 'i 



o j 

Ell 

1I 

ill 



ill i 


if k ill 
111 ill III 


1, ■■! ii 

111 t| -1 

Ml 1:1 II 


3 1 


s s 1 


s ! !- 



zS.8. zsl rB.8-5 



I I 



a IL 
1 1 

I I 



I i 



51 a 



51 



5s 



51 bl bs 



n fiii II II Ii III ill â !î fill 



IjS |s 
5 J s &% 



1.1 It! ^^.? 11 



1 
i 1 

I I 



III I 






2 I 2 

" I " 
S £ S 



!■■ 



I 
s 2 



fcM 



i =& 



1^2 i|2 ||2 


1^ 1 


5 ÎS 


S 1 * 


2S2 P. 12 112 


iÎ2 i 


|2 ^|2 ||2 


l|2 1 



■Ê-,„. 



ill 



11 = 

■g:§-.2 
III 

• 8 is 



111 



isi 



5-552 

i Î' Ë 

llsl 






I I 



se 






§ I 
5 IS 
s ^1 



m lu 



il |,î 

z 2 z 



In 



•hl. 



I liîi ij I -1- nil 

Ci ^ a « Jzïa Jz 5 >■ z zzSz 



Il m 



le. 

lîl 



II 



'i 


1 ■ 














1 § = 


«1 


5 ° 


? ° 


1 ° 


8 2 








i ^■ 


! 


o 






o 








z 


a 














2 -- 


f 1 


1 . 














1 1 


C 1 


i ° 


i 3 


1 2 


1 2 








1 13 


p\ 


2 - 


i - 


i ^ 


1 2 








1 23 


\r\ 


i = 


1 2 


i 2 


3 2 








1 '- 


\t\ 


2 ■ 


"i " 


1 " 










i 2- 


\h\ 


li . 


2 a 


n . 


^ 








2 «- 


1 u 1 












h 


h 


■g 


1 ^1 




1 2 


1 ° 


1 § 




2 


1 


i|i^ 


1 ^ 


-J 2 


■!; 


"52 








1 


r 

512 = 






|2 


1= 


1 






i 


g 


1 >- 


















! 2 




















1 








1 






1 


|i! 


M 


If 


ll. 


ill 


ll 






■a 

■s 

.1 


1 


nil 


li 


ill 


III ill 




1 


il 



Se 



Il I 

^1c B 



a 5 o 






^11 



£ s-s 
56 =iS 



11: 



i.» i 

?5l 1^ 



ùS B z 



Il III 



Mi 

Za z 



lu 



llll 

îïii 



ill 



* 




§ 


' 


l 


i 


h 


3 


i 


\' 




5 






V 








l' 




1 


u 




V 


3 






-1 i/> 






te 






u 






- 




i 



111 



m 



I! I fill îl 

1111 iiïi 111 



2 le 



% 1 

i , 
5 1 



îîï 



I 

IS 

J1 



»<s 






11 



III 



îi 

il 

ii 
il 
il 



I ii 
I --I 
I M 
|!»| 

li'l 
\h\ 
i '1 
I 'I 






§5 

^5 



- I ^ 



il J 

II ll§. 



i\ Il il II nil 



Jil 

!>p i 



8. s s 
_ I 11 I 

III ill ii I 



n .1 
111 II 



If 



1.1 



I ^1 



s s 



§ 2 



I 
1 

1 ^ 

i 2 

II. 

iV 



ai 



'M 
Il s 

.? i s 
èsi i e 

ni 



s?? 
S il 



Il 



•■Il 






■y 


V 


ï 5 ! ! 

? . . . 


1 
1 


1 2 


14352 

S" 


1" 

g 


i 2 1 2 


1 


2 3 


s«2r 


.,,- 


i " 2 2 


i 


: " 


^l"- 


il 


sa.. 


s 


a 


i "S* 


]»- 


i 3 1 i 


1 


1 ^ 


i 222 


i 3 22 


s|= f|=- 




. ; 2 


. ! 2 ï^ " 


iî==- 


m î 


5 


'h 


jj=- 


II-.- 


1, 










i< 1 


1 

11 


if 

h 


:1 

1 


1 



il iili II 



p 

k 



11! 



I 

Il I 
i4ï ê 



II! ill ill II li 



'1. 

; "-s 

II? 



s 5 ? 



1 § 



(5 

g. 

1 



s 5 I 



i ! 



! 3 I 



5 5 3 s^ 



-1,- lin 

!^ I! 

I il 



I 1 

8 2 



3 !^ 



lîii 
111! 



8. -g s 



llll 



li 



il-ii 11 



ni 
111 



lin .... 

1 |f"il =-2.l| 

III tO îlili 
îîl litl lilH 



.1 
tl 

ill 



u 

l 

o 

i 



M 



.< { s 



sî a 

"5 S 



? 8 



lu 



ii§i I 



if.i il 

^15 1^2 



I I 



5^5 ? 



JJ. 



111 



s S ? 

c,33 



ê j, 6-ï 

.fïl a- 

a 



I 



ill il i! 

■111 II 11 
is '3 i£ is 


s J 

II 


g<3 
11 
i£ 


•M - - 


" 


a 



III 2-1 



il? 
Jil 



I 'I 
I =1 
1 11 
I '\ 

I M 

||6| 



«g 
S: z 

< 



111 m 



^^Ml 1l.il 



111 



iiil 111: 
liii III. 



il 



I IS! 






I ill III 

I ^ll III 



i 1 1 



1 II IÎ Ih ili 



= I i I js I 

Is i° Î -lis 



1 ^ 1 


1 


1 


1 ^1 


Z 


= 


1 "^1 




1 


1 '' 1 


! 




\U\ 






||i3 1 


% 


i 


g 






i u i 


2 


i 



Itc 



§232 



1 3 



i|= ^r 



Kit 



g^ is 



IS il 
^11 



il 



HI HI 
I" i i f i i 
il i tz i 



Ill m 

in 111 



I- 

lit 



III 



111 

ill 



11. 
111 



fil 

111 
||l 

iH 
in 



I ? 



fil 

111 



II i\ 

a la < i . 

III ill 

^ 1 1 I i I 

■$5i I si. 



!i II 



.1 i 

c I £ 



= 1 




M 




X ! 




^ 




""1 




1 ^' 




fs 




\h 




1 D 




1 ° • 




Ir 








Ë p 




i £ 




i ' 




\ i 




^ 




i o 












^£5 




1 =|ï 




\ii 




\"t 












\ H 




! o5 




IP 








i 2 ^ 




! c L/ 




i >- 








1 ûC a. 
i .? 


S 


ISS 


S 














1 i 


1 


i 


z 


I 


2 


ll 


1 

3 










i 


2 


! 


9 


i 






X 


il 


i 



j -2 I I i .2 

ill flï 



îîl III 

Hi iif 



i I 



si 



llî 
I 



H 



s g -s 

il! 



Il 
II 



MV/itfii Ibrtabolti 



SECTION 7 
PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



•HVlilbi lb/?CL(7. rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

7 PREFERRED (BEST AVAILABLE) TECHNOLOGIES 

Information on selected plant operations and practices in Ontario, the rest of Canada, U.S.A., Europe. 
Australia and New Zealand is presented in Section 6. This information served as the basis for the 
identification of preferred generic technology trains for the treatment of liquid effluents from the Metal 
Mining Sector in Ontario. 

Technology trains (BAT's) described below apply principally to the treatment of cyanide, heavy metals, 
suspended solids and to the control of pH. No technologies, with two exceptions (tailings ponds and 
engineered wetlands), were found in use. or which could feasibly be applied to the metal mining 
industry, for the control of other parameters such as: dissolved solids, ammonia, nitrate/nitrite, volatile 
organics, and phenolics. 

In most cases, the concentrations of these latter parameters are too low to allow effective application of 
the potential treatment technologies described in Section 3. Best Management Practices (BMP) and/or 
alternative reagents can be used in some instances to control or reduce certain of these parameters, 
most notably ammonia and associated nitrate/nitrites (See Section 9.2). 

Tailings ponds are incorporated into the BAT trains described in this section. Engineered wetlands are 
not recommended for inclusion in selected BAT trains for two reasons. First, the development and 
management of engineered wetlands (primarily through modification of muskeg zones in Ontario) is 
totally dependant on individual site conditions. Second, the effectiveness of engineered wetlands is 
primarily limited to the active growing season (which in northern Ontario extends from late May to mid 
September). 

No attempt has been made to select single 'best' technologies, or to rank the technologies, as different 
technologies are in some instances clearly linked to site specific circumstances. Of note in this regard 
are varying ore types, available facilities for tailings and settling ponds, recovery process specifics, and 
environmental sensitivities. For these same reasons, it must be emphasized that it is not possible to 
predict the quality of the effluent that would result from the application of any BAT option to any 
particular site, without first conducting site specific testwork. This limitation notwithstanding, each of the 

PREFERRED (BEST AVAILABLE) TECHNOLOGIES 7 - 1 



wp/ 1 763-1 5/5cct7.rep/a 

technology trains presented below is capable of attaining or surpassing US EPA BAT/NSPS standards. 
subject to site specific conditions, appropriate design and testwork, and properly controlled operation. 

Tables 7-1 and 7-2 summarize final effluent quality, for selected operting gold and base metal inventory 
plants (Table 6-1. Section 6). for the preferred (Best Available) wastewater treatment technology trains. 
Data are expressed as monthly means, ranges for monthly means, and number of reporting plants for 
each parameter. Individual sample results, by definition, would be more extreme than average values, 
and would therefore exceed upper limits shown. 

Interpretation of the data again requires caution because of the effects of varying ore types and site 
conditions The data, nevertheless, illustrate that the range of mean monthly effluent concentrations, 
attained by the different operating plants, are broadly comparable, and that for each prouping of 
technology trains, no single train stands out as providing the 'best effluent'. 

Tables 7-3 through 7-5, list and evaluate (yes/no) the various technologies relative to the five 
performance criteria: used world wide, used in Ontario, satisfy US EPA BAT/NSPS criteria, produce a 
non-lethal effluent, and provide an advance towards virtual elimination of persistent toxic contaminants. 

The lethality of gold mine effluents to Daphnia magna and to rainbow trout, is difficult to assess because 
of the lack of data (refer to Section 3.12). 

Virtual elimination of persistent toxic contaminants can not be achieved by any of the BAT options, even 
though these technologies, combined with Best Management Practices, will result in significant progress 
towards virtual elimination. In certain geographic areas where conditions of net annual evaporation 
occur, for example in much of western USA, Australia and South Africa, zero volume discharge is 
practised by many mining/milling operations through natural evaporation. 

Ontario's climate, characterized by net annual surplus precipitation, is not suited to this practice. Zero 
volume discharge in Ontario could only be attained through thermal evaporation of any net effluents. No 
metal mining operations (world wide) are known to use this technique because of high capital and 
operating costs. Generic evaporation cost details are provided in Appendix F. 



7 - 2 PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



wp/3763-15/»ect7.rep/a 

The preferred technology trains are described in terms of: 
Design criteria 

• Capital costs 

• Operating costs 

Capital and operating costs at this level of development are considered to be accurate to within 25%. All 
costs are expressed in fourth quarter, 1991 Canadian dollars. 

The capital costs are based on: 

• Sizing of the major items of mechanical equipment 

A detailed estimate of the installed cost of the major items of mechanical equipment. 

• Factored estimates for the civil/structural, piping, electrical and instrumentation components. 

No allowance has been made for the cost of supplying the influent to be treated, or discharging the 
treated effluent, i.e. the battery limits are the end of the discharge pipe conveying the influent and the 
outlet from the final effluent treatment vessel. 

Design values and costs are developed for generic treatment plants optimizing the preferred, best 
available treatment technologies. Reference to any existing plants is not intended. Two levels of 
tonnage or effluent flows are used only for the purpose of establishing a possible range of costs. The 
connection between mine production rate and effluent flows used in the analyses Is typical but varies 
widely in practice. A smaller production rate can easily be associated with a larger effluent flow due to 
operating practice, site specifics and influent flows. 

A summary of the capital costs is provided in each sub-section. Details of the capital cost estimates 
appear in Appendix E. 

Operating costs are sub-divided into reagents, licence fees (if applicable), electrical power, operating 
and maintenance labour and maintenance supplies. The annual cost of maintenance supplies is 
estimated at 5% of the installed cost of mechanical and electrical equipment. Details of the stated costs 
are contained also in Appendix E. 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 7 - 3 



^,B/3763-i5/sect7.rep/a 

7.1 GOLD SECTOR 

De sign Criteri a 

The capital and operating costs for preferred best available technology trains In the Gold Sector are 
developed for both low and high tonnage cases. The design criteria which are common to these two 
cases are as follows: 

Case A Case B 

Solids in tailings (t/d) 750 3 000 

Solids in tailings (%) 40.0 40.0 

Specific gravity of dry solids 2.H 2.8 

Preferred Technology Trains 

The preferred technology trains which are effective in the control of suspended solids, pH, heavy metals 

(Cu, Pb, Zn, Ni) and cyanide in this sector are as follows: 

. Natural Degradation (N.D.) (seasonal discharge with two pond system) 

. INCO SOj-Air (on slurry) /Tailings Pond/Polishing Pond 

. N.D./INCO Sp2 -Air/Polishing Pond 

• N.D. /Hydrogen Peroxide/Polishing Pond 
. N.D./INCO SC^ -Air/Clarification 

. N.D./Hydrogen Peroxide/Clarification 

Of note is the fact that natural degradation occurs in a stand-alone or pre-treatment role In all but one of 
these trains. The exception is the train which Includes treatment of mill tailings slurry (by the INCO 80^- 
Air process) prior to solids removal in the tailings pond. 

The additional control of arsenic and antimony is achieved by the inclusion of a ferric ion precipitation 
step in each of the above trains as indicated below. 

N.D. /Ferric Ion precipitation/Polishing Pond (seasonal discharge with two pond system) 

• INCO SC(j -Air/Ferric ion precipitation/Tailings Pond/Polishing Pond 

• N.D./INCO SO^ -Air/Ferric ion precipitation/Polishing Pond 

. N.D./Hydrogen Peroxide/Ferric ion precipitation/Polishing Pond 

• N.D./INCO SO(j -Air/Ferric ion precipitation/Clarification 

• N.D./Hydrogen Peroxide/Ferric ion precipitation/Clarification 

The Incremental capital and operating costs for the addition of a ferric ion precipitation step to each of 
these trains are given in Section 7.1.7. 

7 - 4 PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



wp/3?63-15/5ect7.rep/« 

The Hemlo Gold process Is a preferred technology train which Is effective In the control of suspended 
solids, pH, heavy metals, cyanide, arsenic and antimony. 

• N.D. / Hemlo Process / Clarification 

The operating costs are based on the use of hydrated lime as the neutralizing agent The choice 
between hydrated lime and quicklime is dependent upon numerous factors which include the following: 

• The geographical location of the effluent treatment plant with respect to potential sources of 
hydrated lime or quicklime 

• The reactivity, rate of slaking, and expected variability In quality of potential sources of 
quicklime 

The expected rate of consumption of lime 

7.1.1 Natural Degradation 

The application of natural degradation as a stand-alone treatment technology is well illustrated by the 
system in use at the Holt-McDermott mine in Ontario. The tailings impoundment system comprises two 
separate ponds which are operated in batch mode. Tailings slurry is directed from the mill to the first 
pond (tailings pond) year-round. During July /August of each year, liquid effluent from the tailings pond 
is transferred to the second pond (polishing pond). This effluent is held for further aging, without release 
and without further input (ofter than precipitation), untB the following spring. Discharge from the 
polishing pond to the environment Is normally restricted to the period of March through June of each 
year. During the holding period water quality In the polishing pond Improves by natural degradation to 
achieve acceptable values for pH, suspended solids, cyanide and various metals (Cu, Zn, Pb. Ni and Fe) 
before being released to the environment. 

Design Criteria 

The design of tailings ponds to yield acceptable liquid effluents solely through the process of natural 

degradation requires data on the following: 

• Surface area and mean depth of the pond 
Initial pH of the pond water 

• Concentrations of total cyanide and dissolved metals (Cu, Zn, Pb, Ni and Fe) in the influent 
stream 

• Flow rate of the influent stream 

• Effluent limits for cyanide and dissolved metals 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 7 - 5 



The Wastewater Technology Centre in Burlington, Ontario, in co-operation witfi Canadian gold mines, 
has completed a number of studies and complied an extensive data base on the natural degradation of 
cyanide and nt'etallocyanide species in gold mill tailings ponds. 



The process J natural degradation has been modelled under batch and continuously filled pond 
conditions The use of the models for designing ponds has been described by Simovic 



Capital and Operating Costs 

The total cost of any tailings facility Includes the cost of the tailings impoundment as well as any 
seepage water and reclaim water collection and pumping systems. A review of these costs which are 
extremely site specific, is not within the scope of this assignment. 

7.1.2 INCO SO . -Air/Tailings Pond/Polishing Pond 

This technology train is shown in Figure 7-1 . The mill tailings, in the form of a slurry, are chemically 
treated before being pumped to the tailings pond. A water balance was calculated around the tailings 
pond to determine the quantity of liquid which overflows into the polishing pond. It was assumed that 
60% of the water in the tailings fed to the tailings pond is recycled to the mill. 



Design Criteria 

INCO S02-Air 

Solids in tailings (t/d) 

No. of operating days per year 

Liquid in tailings (t/d) 

Specific gravity of tailings slurry 

Flow rate of tailings slurry (mP/d) 

Plant availability (%) 

Design flow rate of slurry (nt'/h) 

No. of reactors 

Mean residence time per reactor (min) 

CN^ in mill discharge slurry (mg/L) 

CN^ in treated slurry (mg/L) 



Case A 



Case B 



750 


3000 


360 


360 


1 125 


4500 


1.346 


1.346 


1 393 


5 572 


90 


90 


64.5 


258.0 


1 


1 


60 


GO 


150 


150 


0.5 


0.5 



Polishing Pond 

Mean solution residence time (days) 

Mean depth of solution (m) 



7-6 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



wp/3763-15/sect7.rfp/a 



Costs (INCO S02 - Air & Pdlshing Pond) 
TOTAL CAPITAL COST 
TOTAL ANNUAL OPERATING COST ($) 
UNIT OPERATING COST ($/n^ solution) 
UNIT OPERATING COST ($/t CN destroyed) 



$1 246 000 

$470 500 

$1.15 

$7 760 



$2 283 500 

$1 396 500 

$0.86 

$5 750 



7.1.3 N.P./INCO SO; -Air/Polishing Pond 

This technology train is shown in Figure 7-2. The mill tailings are discharged directly into a tailings pond 

where natural degradation occurs prior to chemical treatment. 

A water balance was calculated around the tailings pond to determine the net quantity of liquid effluent 
to be treated. It was assumed that 60% of the water in the tailings fed to the tailings pond is recycled to 
the mill. The capital and operating cost of the tailings pond are excluded. 

The effluent treatment plant is designed to be operated for 180 days during the spring and summer 
months of each year. 



Design Criteria 

INCO S02-Air 

No. of operating days per year 

Solution to be treated (nf) 

Plant availability (%) 

Design flow rate of solution (nnp/h) 

No. of reactors 

Mean residence time per reactor (min) 

CN^ in feed solution (mg/L) 

Cf\ in treated solution (mg/L) 



Case A 



Case B 



180 


180 


707 000 


2 161 000 


90 


90 


182 


556 


1 


1 


40 


40 


25 


25 


0.5 


0.5 



Polishino Pond 

Solution residence time at design flow rate (days) 

Mean depth of solution (m) 



Costs (INCO S02-Air & Polishing Pond) 

TOTAL CAPITAL COST 

TOTAL ANNUAL OPERATING COST ($) 



$1 261 000 
$144 000 



$2 309 000 
$286 500 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



7-7 



wp/3763-15/sect7.f<?p/a 

UNIT OPERATING COST ($/n^) 

UNIT OPERATING COST ($/t ON destroyed) 



$0.20 
$8 320 



$0.13 
$5 420 



7.1.4 N.D./hvdroqen Peroxide/Polishing Pond 

This technology train which is illustrated in Figure 7-3 is the same as that described in 7.1.3 except that 
hydrogen peroxide is used instead of S0|2-Air In the chemical treatment process. 



Design Criteria 

Hydrogen Peroxide 

No. of operating days per year 

Solution to be treated (n^) 

Plant availability (%) 

Design flow rate of solution (n-P/h) 

No. of reactors in series 

Mean residence time per reactor (min) 

CN^ in feed effluent solution (mg/L) 

CN^ in treated effluent solution (mg/L) 



Case A 



Case B 



180 


180 


707 000 


2 161 000 


90 


90 


182 


556 


2 


2 


20 


20 


25 


25 


0.5 


0.5 



Polishing Pond 

Solution residence time at design flow rate (days) 

Mean depth of solution (m) 



Costs (Hydrogen Peroxide & Polishing Pond) 

TOTAL CAPITAL COST 

TOTAL ANNUAL OPERATING COST ($) 

UNIT OPERATING COST ($/m') 

UNIT OPERATING COST ($/t CN destroyed) 



$1 286 000 


$2 321 000 


$303 000 


$775 500 


$0.43 


$0.36 


$17 510 


$14 660 



7.1.5 N.D./INCO SO ; -Air/Clarification 

A clarification step is substituted for a polishing pond in this technology train which is illustrated in 
Figure 7-4. The effluent from the oxidation process is treated in a reactor clarifier. The sludge recovered 
in the clarifier is returned to the tailings pond for disposal. 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



wp/3763-15/sect7, rep/a 

The choice of a reactor clarifier for this duty is somewhat arbitrary. Other types of suitable equipment 
are employed Including Lamella type plate clarifiers. Clarifiers can also be used In combination with 
active sand filters. 



Design Criteria 

INCO S02 - Air 

No. of operating days per year 

Solution to be treated (rr^) 

Plant availability (%) 

Design flow rate of solution (m'/h) 

No. of reactors 

l^ean residence time per reactor (min) 

CNr in feed solution (mg/L) 

CNr in treated solution (mg/L) 



Case A 



CaseB 



180 


180 


707 000 


2 161 000 


90 


90 


182 


556 


1 


1 


40 


40 


25 


25 


0.5 


0.5 



Clarification 

Design flow rate of feed (nf /h) 
Specific clarification area (nf /nf/h) 
Flocculant addition (g/rrf) 



182 
2.5 
10 



556 
2.5 
10 



Costs (INCO S02 - Air & Clarification) 

TOTAL CAPITAL COST 

TOTAL ANNUAL OPERATING COST {$) 

UNIT OPERATING COST ($/nn?) 

UNIT OPERATING COST ($/t CN destroyed) 



1 921 000 


$2 806 000 


$177 000 


$368 500 


$0.25 


$0.17 


$10 230 


$6 970 



7.1.6 N.D./Hvdroqen Peroxide/Clarification 

This technology train which is shown in Figure 7-5 is the same as that described in 7.1.5 except that the 
INCO SOjj-Air step is replaced by the use of hydrogen peroxide. 



Design Criteria 

Hydrogen Peroxide 

No. of operating days per year 

Solution to be treated (nn?) 

Plant availability (%) 



Case A 

180 

707 000 

90 



Case B 

180 
2 161 000 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



7-9 



wp/3763-15/sect7.rep/a 

Design flow rate of solution (nf /h) 

No. of reactors in series 

Mean residence time per reactor (min) 

CN^ in feed solution (mg/L) 

CN^ in treateo solution (mg/L) 



182 

2 

20 

25 

0.5 



2 
20 
25 
0.5 



Clarification 

Design flow rate of feed (n^/h) 
Specific clarification area (nrf/m'/h) 
Flocculant addition (g/nrp) 



182 
2.5 
10 



2.5 
10 



Costs (Hydrogen Peroxide & Clarification) 

TOTAL CAPITAL COST 

TOTAL ANNUAL OPERATING COST ($) 

UNIT OPERATING COST ($/rrP) 

UNIT OPERATING COST ($/t CN destroyed) 



1 945 000 


$2 926 000 


$336 000 


$858 500 


$0.48 


$0.40 


$19 420 


$16 230 



7.1.7 Ferric Co-precipitation 

The ferric co-precipitation step requires two reactors in series and a ferric sulpfiate mixing and metering 
system. The inclusion of this step In the N.D./INCO SO^ - Air/Polishing Pond train is shown in Figure 
7-6. 



Design Criteria 

No. of operating days per year 

Design flow rate of solution (rrP/h) 

Plant availability (%) 

No. of reactors in series 

Mean residence time per reactor (min) 

As in feed solution (mg/L) 

As in treated solution (mg/L) 

TOTAL CAPITAL COST 

TOTAL ANNUAL OPERATING COST ($) 

UNIT OPERATING COST ($/m') 



180 


180 


182 


556 


90 


90 


2 


2 


15 


15 


S 


5 


0.2 


0.2 


S548 000 


$752 000 


$15 000 


$30 500 


$0.02 


$0.01 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



wp/3763 1b/!iecl/. rep/a 

7.1.8 N.D./Hemlo Process/ClarKlcatlon 

This technology train is illustrated In Figure 7-7. The capital and operating costs of the carbon columns 
shown In Figure 7-7 are excluded from this estimate. 



Design Criteria 

Hemlo Process 

No. of operating days per year 

Solution to be treated (m') 

Plant availability (%) 

Flow rate of solution (nr'/h) 

No. of reactors in series 

Mean residence time per reactor (min) 

CNr in feed solution (mg/L) 

CN^ in treated solution (mg/L) 



Case A 



CaseB 



180 


180 


707 000 


2 161 000 


90 


90 


182 


556 


3 


3 


15 


15 



0.5 



0.S 



Clarification 

Design flow rate of feed (rrP/h) 
Specific clarification area {rrf/n?/h) 
Flocculant addition (g/nf) 



182 
2.5 
10 



556 
2.5 
10 



Costs (Hemlo Process & Clarification) 

TOTAL CAPITAL COST 

TOTAL ANNUAL OPERATING COST ($) 

UNIT OPERATING COST (S/nf ) 

UNIT OPERATING COST ($/t CN destroyed) 



$2 713 000 


$4 068 000 


$238 500 


$536 000 


$0.34 


$0.25 


$61 150 


$45 040 



7.1.9 Treatment of Mine Water 

Mine water occurs as two primary types, either as acid mine water derived from underground and/or 

open pit workings where sulphides are present, or as non-acid mine water associated with low sulphide 

or non sulphide ores. Gold ores tend to be of the latter type, but there are exceptions. 

At sites where acid mine water is generated, surface drainage and stormwater may also show similar 

characteristics. 

For consideration of the treatment of acid mine water, see Section 7.2. 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



>«p/3763- 1 5/sect T. rep/a 

Contaminants in non-acid mine water include: suspended solids, associated heavy metals (mostly in 
solid phase), ammonia from blasting agents, and residual oil and grease. Ammonia is addressed 
separately as a Best Management Practice in Section 9.2. 

Removal of suspended solids from mine water is typically achieved through the combined use of 
underground and/or pit sumps, followed by settling in mine water ponds. Alternatively, where available 
mine water nrioy be directed to the tailings system. 

Design of Settling Ponds 

The mechanism of solids separation in settling ponds, in the absence of any chemical pretreatment (e.g. 
coagulation/flocculation) of the feed, is "free" or "ideal" settling in which solid particles settle 
independently of one another. This settling regime is governed by StCil<e's Law which expresses the 
settling velocity of particles, assumed to be spherical, in terms of their physical properties (diameter and 
specific gravity) and the kinematic viscosity of water. In some instances coagulating/flocculating aids 
may be of value. 

The design of a settling pond is dependent upon the following factors: 

• The expected range of concentration of suspended solids in the influent 

• The size distribution of suspended solids in the influent 

• The expected range of water temperature 

• The expected range of flow rate of the influent 

. The maximum allowable concentration of suspended solids in the effluent. 

The first step in the design procedure is to determine the diameter of the smallest particle to be settled 
out in order to meet the effluent limit. The size of this particle is calculated from the flow rate of influent 
and the size distribution of suspended solids in the influent. 

The surface area of the pond is then calculted by assuming that all particles with a settling velocity 
greater than the overflow velocity will settle out. 

The dimensions of the pond are chosen to ensure that scouring does not occur and that turbulence and 
short circuiting are minimized. 



7-12 PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



wp/3763 15/»ect7.rep/» 

Long, narrow, rectangular ponds are generally affected less by turbulence and short circuiting. As a 
general "rule of thumb" the ratio of the length to the width should not be less than 5:1 . Baffles can be 
used to control oil and grease, where this is a problem. 

Capital Costs 

The cost of a settling pond can vary greatly depending upon a number of factors such as: 

• The extent of excavation required 

• The need for blasting 

• The surrounding topography 

• The extent of diversion of storm water runoff around the pond 

• Access to the pond for cleaning 

Assuming a flat site and no need for blasting, the estimated cost of a typically sized settling pond (60 m 
long X 12 m wide x 5 m deep) with dikes having side slopes of 2:1 and a crest width of 3 m would be 
$60 000. This includes the cost of site preparation and the inlet and outlet assemblies for the waste 
water. This estimate is based on a unit cost of $8/rT? for earthworks. 

Operating Costs 

Labour and machinery are required for maintenance of a settling pond to avoid adverse effects on it's 

operation. Typical items on the maintenance list are as follows: 

• Cleaning of the pond on a regular schedule (annual or less frequent basis) to ensure peak 
efficiency at all times 

• Disposal of settled solids in a disposal area such that they do not wash back into the pond 
or cause off-site sedimentation problems 

• Maintenance of slopes or banks 

Periodic checking and repair of pipes, weirs and structures 
Maintenance of storm water diversion ditches 

It is estimated that total operating costs should not exceed $10 000 - 20.000 per year. 

7.2 BASE METAL SECTOR 

Mine waters arising from base metal mines in Ontario are commonly acidic. Sulphuric acid is generated 
by the chemical and biological oxidation of the sulphide minerals in the presence of oxygen and 
moisture. The neutralization of this free acid and the concurrent removal of dissolved metals by their 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 7 - 13 



wp/3763-15/sect7.rep/a 

precipitation as hydroxides is the most common method of chemical treatment at both active and non- 
active mines This treatment technology is also applied to excess water from tailings ponds. 

The metals most commonly present in these wastewaters are copper, iron, lead, nickel and zinc 
Effective precipitation of the hydroxides of these metals can be achieved at a single pH between 9 and 
10. Thus single-stage precipitation of metal hydroxides followed by single-stage solid/liquid separation 
is the commor practice at Canadian mines. 

Sulphide precipitation potentially can achieve lower dissolved metal levels than those achievable by 
hydroxide precipitation due to lower solubilities of metal sulphides compared with the corresponding 
metal hydroxides. 

In special circumstances (e.g. smelters/ refineries), when the array of dissolved metals is somewhat 
different from that occurring at most Canadian base metal mines, it may be cost effective to recover the 
metals in groups by selective precipitation at more than one pH. The metals could be precipitated with 
different anions (e.g. sulphide, and hydroxide). 

Acid mine water is commonly treated by the hydroxide precipitation method. Water from stand-alone 
mines which cannot be clarified in a tailings pond is generally collected in a surface mine water pond to 
provide surge storage prior to treatment and to reduce suspended solids content. The high density 
sludge method is often employed to maximize capture of metal precipitates where a tailings pond 
system is not available for discharge. A clarifier with recycled sludge is used. The final sludge must be 
disposed in a sludge pond or may be removed to landfill or backfill sites. 

Hence, the preferred technology trains for the control of pH, suspended solids and heavy metals in 
liquid effluents arising in the base metal sector are: 

Tailings Pond/Hydroxide Precipitation/Polishing Pond 

Tailings Pond/Hydroxide Precipitation/Clarification 

Tailings Pond/Sulphide Precipitation/Clarification 

Multistage Precipitation/Multistage Clarification 

Undenwater Disposal 

7.2.1 Tailings Pond/Hydroxide Precipitation/Polishing Pond 

In this technology train the mill tailings are discharged into a tailings pond for primary solid /liquid 
separation. The overflow from the tailings pond is treated with lime to precipitate dissolved metals as 

7-14 PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



wp/3763-15/»ect7.fep/« 

hydroxides at a pH of 9 to 10. The treated effluent Is then fed to a polishing pond for secondary 
solid/liquid separation to produce a final effluent which is discharged to the environnnent. 

The transfer of the overflow from the tailings pond to the settling pond and the addition of the lime can 
be achieved In a number of different ways. 

For example, the tailings pond overflow can be collected in a decant tower. The decant solution then 
flows by gravity via a pipeline or an open channel into the polishing pond. The lime is added, In slurry 
form, as close as possible to either the decant collection or discharge point to maximize the mixing and 
reaction time before entry into the polishing pond. 

The mechanical equipment required for hydroxide precipitation using this scheme will consist of a lime 
silo, a lime feeder, an agitated lime slurry mix tank and lime slurry pumps which supply a loop through 
which lime slurry is pumped continuously. 

In a second scheme, which is shown in Figure 7-8. the excess flow from the tailings pond is recovered 
by water pumps into the first of two reactor tanks in series. The lime slurry is added to the first reactor. 
The overflow from the second reactor flows by gravity or is pumped to the polishing pond. Mechanical 
equipment for this scheme will comprise two reactors with mechanical agitators in addition to the 
equipment required for the first scheme. 

The capital and operating costs for this second scheme are developed for design flow rates of solution 
of 75 and 300 rrP/h. A lime addition of 0.2 kg/n^ is used in the estimate of the operating costs. 



Design Criteria 

Hvdroxide Precipitation 

Design flow rate of solution (nnP/h) 

No. of operating days per year 

Plant availability (%) 

Solution treated (nnp/a) 

No. of reactors in series 

Mean residence time per reactor (min) 



Case A 



Case B 



75 


300 


360 


360 


90 


90 


583 000 


2 333 000 


2 


2 


15 


15 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



wp/3763-15/sect7.rep/a 



Polishing Pond 

Mean solution residence time (days) 

Mean depth of solution (m) 



Costs (Hydroxioe Precipitation & Polishing Pond) 
TOTAL CAPITAL COST 
TOTAL ANNUAL OPERATING COST ($) 
UNIT OPERATING COST ($/n^) 



)33 500 


$1 497 000 


61 500 


$233 000 


$0.28 


$0.10 



7.2.2 Mine Water Pond /Hydroxide Precipitation/Clarification 

This train, depicted in Figure 7-9, incorporates sludge recycle to produce a high density sludge for 
disposal. The first stage in the train can egually be a tailings pond or settling pond, in the case of acid 
mine water alone, for removal of suspended solids. 

The capital and operating costs are developed for plants treating acid mine water at design flow rates of 
75 and 300 nnp/h. 



Design Criteria 

Hydroxide Precipitation 

Design flow rate of solution (m*/h) 

No. of operating days per year 

Plant availability (%) 

Solution treated (m'/a) 

No. of reactors in series 

Mean residence time per reactor (min) 



Case A 



Case B 



75 


300 


360 


360 


90 


90 


583 000 


2 333 000 


2 


2 


30 


30 



Polishing Pond 

Mean solution residence time (days) 

Mean depth of solution (m) 



Costs (IHydroxide Precipitation & Clarification) 
TOTAL CAPITAL COST 
TOTAL ANNUAL OPERATING COST ($) 
UNIT OPERATING COST ($/nn') 



$1 958 000 


$3 661 500 


$359 500 


$955 000 


$0.62 


$0.41 



7- 16 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



wp/3^63 1S/»ect7.f«p/B 

Operating costs for this technology train are based on the use of hydrated ilme as the netrtraiizlng agent. 
The choice between hydrated lime and quicklime is dependent upon numerous factors which include the 
following: 

• The geographical location of the effluent treatment plant with respect to potential 
sources of hydrated and quicklime 

• The reactivity, rate of slaking, and expected variability in quality of potential 
sources of quicklime 

• The expected consumption of lime 



7.2.3 Tailings Pond/Sulphide Precipitation/Clarification 

The solution In tailings ponds associated with base metal mines is most often neutral or alkaline as a 
consequence of the increased pH value usually inherent in the flotation processes. The neutral or 
alkaline pH level in the pond results in precipitation, to a very high degree, of metal ions. 

This train, shown in Figure 7-10, incorporates precipitation of the residual dissolved metals as sulphides 
and two stages of clarification. The primary clarification is achieved in a Lamella plate clarifier while an 
active sand filter is used in the second polishing stage. 

The capital and operating costs are developed for plants treating effluent at the rate of 75 and 300 nf/h. 
It is assumed that the alkalinity of the feed solution is great enough to ensure a pH of at least 6.5 in the 
treated effluent. 

Design Criteria Case A Case B 

Sulphide Precipitation 

Design flow rate of solution {nf /h) 

No. of operating days per year 

Plant availability (%) 

Solution treated (nr?/a) 

No. of reactors in series 

(^ean residence time per reactor (min) 

Content of dissolved metals (mg Cu equivalent/L) 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 7-17 



75 


300 


360 


360 


90 


90 


583 000 


2 333 000 


2 


2 


15 


15 


5 


5 



$1 547 000 


$3 299 000 


$184 000 


$268 000 


$0.32 


$0.11 



wp/3763-15/sect7.rep/a 

Costs (Sulphide Precipitation & Clarification) 
TOTAL CAPITAL COST 
TOTAL ANNUAL OPERATING COST ($) 
UNIT OPERAIING COST {$/n?) 



7.2.4 Multistage Precipitation/Multistage Clarification 

Each of the metal hydroxides has a specific pH at which its solubility is a minimum. Furthermore, the 
theoretical solubilities of metal sulphides are generally orders of magnitude lower than those of the 
corresponding metal hydroxides. The solubility of most metal carbonates is intermediate between the 
solubilities of hydroxides and sulphides. The metal sludges produced from sulphide and carbonate 
precipitation are also often easier to dewater than their hydroxide counterparts. 

It is possible, therefore, through judicious choice of the precipitating agents and pH's to effect partial -y 
complete separation of a suite of dissolved metals. In this manner it is possible to produce a final lioulc 
effluent with metal concentrations lower than those possible by hydroxide precipitation alone. In certai*"- 
circumstances the recovered metals can be recycled in the same process (e.g. to a smelter) or sold for 
onward processing at a different site. 

This technology train is typified by the effluent treatment plant of Metaleurop Weser Zink located in 
Nordenham, Germany. This treatment plant treats wastewater from both zinc and lead smelters at the 
rate of 50 m'/h and has been described in Section 6.2.4. 

The range of concentrations of contaminants in the influent stream for a recent month was as follows: 

Minimum mq/L Maximum mq/L 

Zn 29 42 

As 1.2 6.0 

Hg 0.8 6.1 

Pb 5.8 15.0 

Cd 3.0 23.0 

pH (units) 1.1 1.9 



7-18 PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



The average quality of the final effluent during 1990, together with the site specific limits are listed below. 



Metal 


Mean 1990 (mq/L) 


Limit (mq/L) 


Cd 


0.0030 


0.5 


Hg 


0.0018 


0.1 


Zn 


0.050 


1 


Pb 


0.006 


0.2 


Cu 


0.01 


0.1 


Fe 


0.22 


3.0 


Cr 


0.022 


0.1 


As 


0.006 


0.1 


Ni 


0.01 


0.2 



The installed cost of this plant, provided by Dr. K. Roennefahrt in a personal communication, is 
estimated to be $15 million. 

7.2.5 Underwater Disposal 

Underwater disposal of tailings containing sulphide minerals is practised at the Polaris Mine of Cominco 
in the Northwest Territories and at the copper/zinc concentrator of Hudson Bay Mining and Smelting at 
Snow L.ake, in Manitolsa. 

This practice, which serves to limit oxidation of sulphide minerals, is being applied successfully at these 
two operations. 

Ultimate mine closure is also facilitated by underwater disposal. 

7.3 IRON ORE SECTOR 

The beneficiation of iron ores involves physical and not chemical processes. Typical unit operations are 

magnetic separation and heavy media concentration. 

Most processing operations are wet and the process effluents are discharged to tailings ponds. The 
recycle of water from the tailings ponds to the concentrator for re-use in the concentrator is maximized. 
In some instances, the tailings are thicl<ened with the aid of flocculants/coagulants (e.g. alum) prior to 
being pumped from the concentrator to the tailings pond. 



PREFERRED (BEST AVAIU\BLE) TECHNOLOGIES 7-19 



/«u/j/ba 1b/sect?.rep/a 

The tailings pond functions as a primary gravity settler with any excess effluent reporting to a polishing 
pond before release to the environment. 

In isolated instances (e.g. Tilden f^^ine in Michigan) the effluent from the tailings pond is routed to a 
reactor/clarifier for secondary removal of suspended solids before final discharge. 

The preferred technology trains in this sector are therefore considered to be: 
. Tailings Pond/Polishing Pond 

• Tailings Pond/Clarification 

Acid drainage from waste rock and tailings, if it occurs, requires the Inclusion of a neutralization step in 
these two trains. 

The provision of "Order-of-Magnitude" capital and operating costs for tailings ponds and polishing ponds 
is not within the scope of this report. The costs for the clarification and neutralization steps can be 
derived from information provided in the gold sector. 

7.4 URANIUM SECTOR 

The single preferred technology train in this sector is the following: 

• Hydroxide Precipitation / Tailings Pond / Radium Co-precipitation / Clarification / 
pH Adjustment / Monitoring Pond 

This scheme, with the exception of the initial hydroxide precipitation step, is shown in Figure 7-1 1 . The 
initial neutralization step is performed in the mill, usually on a single combined stream containing all 
effluents including solid tailings. This slurry is aerated to oxidize fen-ous ions to ferric which are 
precipitated, along with other dissolved heavy metals, as hydroxides 

After this initial hydroxide precipitation step the slurry is pumped to a tailings pond where separation of a 
liquid effluent takes place. The major contaminant in this liquid effluent is the radionuclide, radium-226, 
due to its relatively high solubility In aqueous media. Removal of dissolved radium is achieved by 
barrum chloride addition to effect co-precipitation with barium sulpfiate. Any dissolved arsenic is 
simultaneously precipitated as barium arsenate. The pH is controlled during the course of these 
reactions by the use of lime. Any dissolved heavy metals present are also precipitated as hydroxides. 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



<«p/376>15/»ec17 rep/a 

The precipitates are recovered in a darifier before disposal in a dedicated sludge pond. The pH of the 
darlfier overflow may require reduction to achieve acceptable effluent standards and this Is normally 
accomplished by the addition of sulphuric acid. The effluent flows to a monitoring pond from where it is 
discharged to the environment. 

Capital and operating costs for the hydroxide precipitation step are provided in Section 7.2.1. The other 
steps in this technology train are concerned with control of the radionudeide, radium-226 and as such 
are excluded from the study scope. 

7.5 SILVER SECTOR 

The recovery processes for silver include unit operations which are used in the gold and base metal 
sectors. The contaminants in liquid effluents from silver operations are found in either or both of these 
two sectors. The appropriate technologies for the removal of these contaminants are described in 
Sections 7.1 and 7.2 

At present there are no active silver mines or mills in Ontario. 



PREFERRED (BEST AVAILABLE) TECHNOLOGIES 



,-J 


z 


, 


m 




^ 


? 




^ 


s 




^ 














' 






























































^ 


^ 


^ 


" 


" 






- 






" 














5 


5 


5 


, 


i 




^ 


9 




^ 


5 




^ 










































rQ 


r 


q 


. 


? 




- 


S 


5 




5 




- 




p 




- 


1 ^ 


3 


? 


^ 


5 




^ 


S 




^ 


q 




^ 


? 




^ 


i 




■ 






















1 

Î 








i Z 


? 


S 


. 


§ 




- 


q 


q 


. 


q 




- 


o 




- 


f ~~ 




S 










<o 


ï; 










z 


■n 






§ " 




s 




ë 








° 


















< 


° 


5 


. 








°. 




- 


? 




- 




? 




- 


































g 


° 


q 


■" 


S 




- 


fe 


q 


~ 


ft 




"■ 




^ 




'^ 


















^ 
















in 


i? 






fe 






''i 


RI 




h; 














K 




S 




a> 






^ 




















i 


a 


5 




S 






■ 

S! 


o 


^ 


. 




^ 






^ 




































1 Î 


s 
1 


f 


I 


1 

5 


î 


£ 


i 
1 


f 


i 


1 


f 


£ 
É 


1 


f 


é 


1 


1 


1 


1 












1 ^ 




S 




1 




c 


1 * 


^ 


<£ 


? 


î 




s 


II 

1 i 


1 


i 


1 


1 


1 


1 


^ % 


1 


1 

c 


5 


t 


ï 


1 




31 


II 


o 


t 

d 


s" 

i 


1 




ig 


?£ 


z 


z 




z 



Q. 

I i 

O I 













1 






















— 




i 


S 




-- 






Î5 




"- 




? 




- 


? 




- 


? 








s 






5 




- 


^ 




- 






















^ 








ii 












8 












^ 


9 




^ 






^ 






















5 


-is 


' 


9 








° 








<^ 






q 
































1 


f 


°. 


^ 


^ 


Î 


1 


I 






1 
1 


h 




- 


S 




- 


<j 


































I 

* 


z 


s 


^ 


~ 


f 

1 
o 


f 
1 

o 


5 








? 




- 


q 




- 




























1 










z 


z 








z 














1 


= 


t 


À 


CN 


i 


i 


Vi 






1 


s 




^ 


s 




^ 


1 


































< 


s 


 








q 








? 




^ 


q 




^ 
































































2 


s 


° 


CN 






S 








5 




'^ 


'^ 




"" 






























S 


OD 










h. 








- 






Ç 




^ 




'' 




















" 
















q? 
























I 


SI 










CM 








^ 






.? 










OJ 


là 
















"" 
















1 


Î 


I 


1 


1 


1 


1 


1 


i 


1 


Î 


1 


5 


1 


i 


1 


1 


î 


1 


î 


Ï 






g" 










f 


f 


? 




1 










t 


1 

i 


Ij 

at 

II 
ÎI 


1 

fit 


! 

1 

Î 


If 


il 


!! 


1 






z S- 


isl 


il 


5° 


5° 


n § 


J 







































I- 


S 


,"■ 


, 


'o 


[n 


, 


























" 






,. 
























































I 


H 




"^ 


^ 




" 


- 




' 


^ 




- 










































5 


? 




" 


o 




■" 


" 




^ 


° 




^ 








.5 


S 


" 

5 

5 


. 


•^ 


9 


- 


S 




- 


g 


i 


c 


^ 






f 


o 


il 




S 


S 




s 






r. 


q 




o. 






s 






8 






8 












8 










^ 


































1 


2 


i 


5 


>n 


s 


5S 


^ 


? 




- 


q 




- 


" 






5 












































_ 






















il 


5 


q 


S 


" 


s 


S 


^ 


? 




- 


8 




- 


" 






s 






































r, 






























5 


° 


5 


" 


5 




n 


q 




" 


° 




" 


" 












































































"' 






" 
























. 


f 


° 




ÎS 


















ï^ 








1^ 


i6 


































^ 






CD 
























i 


5 


•p 


CO 


m 


<?' 


ID 








5 




- 


" 










1 


1 


1 




1 


1 


5 


î 


I 


s 


î 


I 


i 

2 


f 


I 






, 


s 




J 








1 


o 




1 


1 


1 


1 


g 


1 




1 


1 


1 


1 


S 


s 

1 




1 




1 


1 


"^?. 


t 


s 






=£ -a 


I 


ï fc 


(O 


jî 






le 


II 




1 


ï 






g, £ 


g, g 


II 


g, 


i 


u 




lÎ 


il 


11 
5 £. 


j 


^ 



Table 7 - 3 

Technology Trains for Control of Suspended Solids, Cyanide and Heavy K^etals 
In Liquid Effluents in the Gold Mining Sector 



Technology Train 


In Use 
World Wide 


In Use In 
Ontario 


Satisfies 
US EPA [1] 


Produces a 

Non-Lethal 

Effluent 


An Advance 

Towards 

Virtual 

Bimination 


Natural Degradation (N.D.) [Seasonal 
discharge with two pond system 


Yes 


Yes 


Yes 


Insufficient 
Data [3] 


Yes 


INCO SC^-Air (on slurryj/Tailings 
Pond/Polishing Pond 


Yes 


NO [2] 


Yes 


Insufficient 
Data [3] 


Yes 


ND/INCO SC^ -Air/Polishing Pond 


Yes 


Yes 


Yes 


Insufficient 
Data [3] 


Yes 


N.D./Hydrogen Peroxide/Polishing Pond 


Yes 


Yes 


Yes 


Insufficient 
Data [3] 


Yes 


N.D./INCO SC^ -Air/Clarification 


No 


No 


Yes 


Insufficient 
Data [3] 


Yes 


N.D./Hydrogen Peroxide/Clarification 


Yes 


No 


Yes 


Insufficient 
Data [3] 


Yes 



[1] For heavy metals and other parameters only, US EPA has no defined limit for cyanide 

concentrations for net precipitation areas and where maximum feasible recycle is practised. 

[2] An application is on file with OMOE for use of INCO SOj-Air on slurry at the Kerr Mine (Approval 
is expected shortly). 



[3] Subject to confirmation by MISA and other data sources. Application of preferred BAT options 
is likely to enable compliance with toxicity requirements in most cases. Non-lethal effluents are 
demonstrated at a number of specific sites. 



Table 7 4 

Technology Trains for Control of Suspended Solids, Cyanide. Heavy Metals 
Arsenic and Antinnony In Liquid Effluents in the Gold Mining Sector 



Technology Train 


In Use 
World Wide 


In Use In 
Onurio 


Satisfies 
US EPA [1] 


Produces a 

Non-Lethal 

Effluent 


An Advance 

Towards 

Virtual 

Elimination 


N.D /l-temlo Process/aarification 


Yes 


Yes 


Yes 


Insufficient 
Data (2) 


Yes 


N.D /Ferric Co-precipitation/Poiishing 
Pond [Seasonal discharge with two pond 
system) 


Yes 


No 


Yes 


Insufficient 
Data [2] 


Yes 


INCO Sq^-Air (on slurryj/Ferric Co- 
precipitation/Tailings Pond/Polishing 
Pond 


No 


No 


Yes 


Insufficient 
Data [2] 


Yes 


ND./INCO Sq -Air/Ferric Co- 
precipltatlon/Polishing Pond 


No 


No 


Yes 


Insufficient 
Data [2] 


Yes 


N.D./Hydrogen Peroxide/Ferric Co- 
precipitation/Polishing Pond 


Yes 


No 


Yes 


Insufficient 
Data [2] 


Yes 


ND./INCO SC^ -Air/Ferric Co- 
precipitation/Oarification 


No 


No 


Yes 


Insufficient 
Data [2] 


Yes 


N D./Hydrogen Peroxide/Ferric Co- 
precipitation/Clarification 


Yes 


Yes 


Yes 


Insufficient 
Data [2] 


Yes 



[1] For heavy metals and other parameters only, US EPA has no defined limit for cyanide 

concentrations for net precipitation areas and where maximum feasible recycle is practised. 



[2] Subject to confirmation by MISA and other data sources. Application of preferred BAT options 
is likely to enable compliance with toxicity requirements in most cases. Non-lethal effluents are 
demonstrated at a number of specific sites. 



Technology Trains for Control of Heavy Metals, pH and Suspended 
Solids in Liquid Effluents in the Base Metal Mining Sector 



Technology Train 


In Use 
World Wide 


In Use In 
Ontario 


Satisfies 
US EPA [1] 


Produces a 

Non-Lethal 

Effluent 


An Advance 

Towards 

Virtual 

Bimination 


Tailings Pond/Hydroxide 
Precipitation/Polishing Pond 


Yes 


Yes 


Yes 


Insufficient 
Dau [3] 


Yes 


Mine Water Pond/Hydroxide 
Precipitation/Oarification 


Yes 


Yes 


Yes 


Insufficient 
Dau [3] 


Yes 


Multistage Precipitation/Multistage 
Clarification 


Yes 
(Smelter/ 
refinery 

only 


No 


Yes 


Insufficient 
Data [31 


Yes [2] 


Tailings Pond/Sulphide 
Precipitation/Clarification 


Yes 


No 


Yes 


Insufficient 
Data [3] 


Yes [21 


Underwater Disposal 


Yes 




Ho 


Yes 


Insufficient 
Data [31 


Yes 



[1] For new mills, yet to be established, New Source Performance Standards (NSPS) apply which 
allow discharge for net precipitation areas only and provided that maximum feasible recycle is 
practised. 

[2] Sulphide precipitation associated with these two techniques is more efficient for the removal of 
dissolved metals compared with hydroxide precipitation 



[3] Subject to confirmation by MISA and other data sources. Application of preferred BAT options 
is likely to enable compliance with toxicity requirements in most cases. Non-lethal effluents are 
demonstrated at a number of specific sites. 




13 



< 

a: z 

UJ <Q. 
Q ' 

OZ 



a3iVM NIV"l33a 




D= 








o 


















o 






u~> 


^ 










CJ 












-==tt] 




y3ivM «IV 133a 




c=caii 





©^ 




4 1 r 








, 


















> 






f 






i 


M 


* 


Ml 1 WAA 


iMwmw 


/ 



wp/3763-15Aabofcon.rep/a 



SECTION 8 
ALTERNATIVE PROCESSES 



wp/J?63 Ib/Gocie.rcp/o 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

8 ALTERNATIVE PROCESSES 

8.1 GOLD SECTOR 

In recent years, research and testwork emphasis relating to alternative processes has t)een placed on 
protection of the environment from pollution and on the treatment of refractory gold ores. This has led 
to renewed interest in the development of treatment processes that are as efficient and as cost-effective 
as direct cyanidation 

8.1.1 Alternative Leaching Reagents 

A number of possible alternative leaching reagents have been considered. Technical aspects of the 
more promising ones are described below. None of these reagents have been used commercially and 
their environmental impact has not been assessed. 

Thiosuiphate Leaching 

Leaching with thiosuiphate must be carried out in alkaline solution since this reagent disproportionates in 
acidic solutions. The only reported successful applications of thiosuiphate have required the use of 
oxygen under pressure and high concentrations of thiosuiphate, together with copper as a catalyst in 
ammoniacal solutions. 

Thiourea Leaching 

Extractions using thiourea in acidic solutions are generally very high. However, thiourea is slowly 
oxidized by the oxidants used in the leach and the products of oxidation (elemental sulphur and other 
products) can cause partial passivation of the gold surface. The rate of dissolution therefore decreases 
with the age of the leach solution and this can lead to excessively high consumption of the reagent, with 
reported values in excess of 5 kg/t. 

Thiocvanate Leaching 

Little has been published about this system other than that leaching in thiocyanate solutions is faster 
than in solutions of thiosuiphate. The use of elevated temperatures and pressures could be expected to 
yield acceptable leaching rates but the decomposition of thiocyanate is a possible complication under 
these conditions. 

ALTERNATIVE PROCESSES 8 - 1 



A further factor to be considered wfien thiocyanate is used, is tfie relatively high insolubility of silver 

thiocyanate. 

Chlorine Leaching 

The rate of dissolution of gold by chlorination is about two orders of magnitude greater than in 

cyanidation mainly because the solubility of chlorine is greater than that of oxygen in aqueous solutions. 

The dissolution of other metals in the ore is appreciable and sulphur, In the form of sulphide minerals, Is 
oxidized to sulphate. The excessively high consumption of chlorine by these unwanted reactions 
renders chlorination uneconomical except under exceptional circumstances. An additional disadvantage 
is that silver chloride is insoluble in concentrated chloride solutions. 

8.1.2 Refractory Ore Processes 

Refractory ores containing sulphides and arsenic bearing minerals have previously been treated by 
roasting. Envinromental concern related to the control of sulphur dioxide and arsenic trioxide produced 
in the roasting process has been one of the factors in the development of alternative processes. 

Pressure Oxidation 

Refractory ores and concentrates can be treated in autoclaves at high temperature and pressure in the 

presence of oxygen. The sulphide minerals are oxidized to jarosite, sulphuric acid and ferric arsenate to 

permit enhanced gold recovery. 

The discharge from the autoclaves is neutralized and then treated with cyanide. The final solid residue, 
containing the jarosites and ferric arsenate, is discharged to a tailings pond The expected stability of 
these compounds is such that their incorporation in the tailings is environmentally acceptable. 

This process has gained wide acceptance with six operating plants. Four of these plants are located in 
the US, one in Ontario, Canada and one in Brazil. 

Bacterial Oxidation 

The oxidation of the sulphide minerals to jarosite, sulphuric acid and ferric arsenate occurs due to the 
action of the bacteria. Thiobacillus ferrooxidans. on the ore particles. The rate of oxidation by this 
means Is much slower than the rate of pressure oxidation. The reaction requires a large amount of air. 
Essential nutrients are added In the form of fertilizer granules. The jarosites and ferric arsenate are 
impounded in the tailings basin. 

8 - 2 ALTERNATIVE PROCESSES 



wp/3763-15/5ecte.rep/o 

This process is being used in the treatment of concentrates at two plants in South Africa, one In Brazil 
and one in Australia. 

Roasting 

The two stage roasting of arsenical flotation concentrates has been widely practised. The main concern 
with these plants centres around the disposal of the A^O, dust produced in the process. At the present 
time there is an oversupply of this commodity on world markets. 

Roasting of the whole ore has enjoyed renewed interest in the last two years with three new plants In the 
US Two of these operations use an oxygen-enriched atmosphere. This proprietary process, when 
applied to arsenenical ores, produces a solid calcine in which the arsenic is retained. 

Sulphide Flotation 

In situations where ores contain the majority of the gold in association with sulphide minerals, gold may 
be recovered in a sulphide concentrate by the flotation process. This concentrate is generally leached 
with cyanide to extract the gold, or in specific cases may be sold to a smelter, thus avoiding cyanide 
leaching at the mine site. This process is generally employed only when the recovery of gold by 
flotation plus cyanidation can equal the recovery attainable by cyanide leaching of the whole ore. Some 
ores of the Timmins area have been amenable to this technique (Pamour and Owl Creek mines). 

When applied, the process does allow segregation of a small fraction of ore into a sulphide stream 
which may represent 5-30% of the total ore treated. After leaching, the sulphide can be stored in a 
tailings area separate from the main quantity of flotation tailings. Thus the area required for storage of 
sulphidic and cyanide leached solids is smaller than when the whole ore is leached, and effluent from 
this area including natural precipitation may represent a lower flow than from the main tailings area. 

While selection of the process depends on ore characteristics and relative gold extraction levels, when 
equivalent gold values can be obtained the impact of effluent control strategy may be a deciding factor. 

8.2 BASE METAL SECTOR 

Alternative Flotation Reagents 

Phenolic compounds are used as a frothing agent at some tiase and precious metals flotation mills. 
Pine oil, which is also used as a frother in the sulphide mineral flotation operation, can contain 
phenolics. Nonphenolic frothers which are potential alternatives to phenol-based or phenol-containing 
compounds include methyl isobutyl carbinol (f^lBC) and polyglycol methyl ethers. Some collectors also 

ALTERNATIVE PROCESSES 8 - 3 



wp/3763-15/sect8.rep/a 



contain phenolic radical groups. Possible alternatives to phenolic collectors include dithiophosphate 
salts and dithiophosphoric acids with alkyl groups in place of phenol groups. Substitution of these 
reagents are site dependent and would require experimentation at each mill to determine the optimum 



Sulphide Flotation 

In the recovery by flotation of base metals from sulphidic ores, one ore more metal concentrates 
representing optimum recovery of the desired metals is produced. The flotation tailings contain waste 
rocl< plus unrecoverable sulphide materials. When processing ores containing significant quantities of 
pyrite, pyrohotite or other non-valuable sulphide minerals, these minerals will also be rejected with the 
tailings stream. 

Depending on ore characteristics and the level of residual sulphides found, it may be possible to recover 
by flotation a large proportion of the residual sulphides in order to reduce the sulphide content of the 
overall tailings. When practical, this sulphide concentrate may be dewatered and stored in an 
impoundment area separate from the main tailings pond. This may allow better control of metal 
containing effluents during operation and during long term management. Indirectly this practice is 
already employed at a number of gold operations (see Section 8.1). 



8 - 4 ALTERNATIVE PROCESSES 



wp/3^(J3 IS/tobofcon.r 



SECTION 9 
BEST MANAGEMENT PRACTICES 



wp/3re3-15/5ect9.rcp/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

9 BEST MANAGEMENT PRACTICES 

Best Management Practices (BMP's) differ from BAT's in that they tend to control pollutants at source 
and provide control of upsets, rather than to provide effluent treatment per se. BMP's are consequently 
not regarded as being equivalent to BAT's, but their development and implementation can be crucial to 
the successful operation of BAT options. 

BMP's can be sutxlivided into five broad categories: 

practices employed to minimize upset conditions 

practices w^hich control pollutant loadings at source 

recycle 

operator training and management strategies, and 

backfill operations 

9.1 PRACTICES EMPLOYED TO MINIMIZE UPSET CONDITIONS 

Spill prevention and clean-up 

Sizing of waste water treatment systems 

Sludge management and waste disposal 

Spill Prevention and Clean-Up 

Spills of site chemicals associated with, or ancillary to the effluent treatment system may result in the 
release of untreated contaminants to receiving waters. There are several BMP's in place at mining 
operations to reduce or eliminate the impact of spills. 

Plant personnel associated with the effluent treatment system and with the handling of reagents are 
generally trained or knowledgeable in spill response measures on the site. To augment these measures, 
sites have a number of physical controls or monitoring devices to minimize the risks and impact of spills. 

Operations generally employ mill sumps to collect process water and spill materials. Effluents In the 
sumps are eventually reused as process water or discharged to the effluent treatment system. In 
addition, most sites have constructed catchment facilities in areas where spills could occur. Ditching 

BEST MANAGEMENT PRACTICES 9 - 1 



vA(p/3763-15/sect9.rep/a 

and storm sewers around storage areas are also employed to direct potentially contaminated effluents to 
the treatment system. Another spill containment practice is the construction of berms around storage 
tank areas to contain spillages or leakages until they can t>e managed in accordance with local 
regulations. 

Several operations are now employing alarm systems and pipeline pressure gauges to monitor pipeline 
and pump integrity. These systems augment the regular inspection of lines and pumps presently carried 
out by site personnel. 

Sizing of Waste Water Treatment Systems 

The sizing of waste water treatment systems takes Into consideration the range of flow volumes which 
must be handled, together with provisions to contain effluents during plant break-downs or during 
periods of equipment maintenance. 

To extent possible, tailings basin drainage areas should be minimize to reduce effluent volumes and 
treatment requirements, and to limit the potential for storm water and spring melt surges. Procedures 
commonly practised within the mining industry to achieve these objectives include the critical selection 
of tailings areas, and diversion of surface waters away from tailings catchment basins. 

Adequate free-board and spillway contingency should be incorporated into the tailings dam design to 
contain and/or control stormwater flows associated with the spring melt and extreme precipitation 
events. 

Where chemical treatment systems are located downstream of tailings ponds, the chemical treatment 
system design capacity should be such that high flow conditions can be handled. Alternatively, 
provisions are required through freeboard design, to temporarily store such waters, so as not to by-pass 

treatment facilities. 

Sludge Management and Waste Disposal 

Many treatment systems in use by the mining industry produce sludges as a by-product of one stage of 
the treatment process. Sludges may be produced either hydroxide or sulphide precipitation. These 
materials require proper handling to reduce the potential for resolubilization of the sludge, and the 
potential for contamination of receiving waters following disposal. 



BEST MANAGEMENT PRACTICES 



v«/p/3763-15/sect9. rep/a 

Many operations which use hydroxide precipitation treatment now employ high-density sludge systems. 
This system produces a more compact, sludge for more effective storage. In addition, rr\any operations 
presently dispose of the sludges within the tailings storage area. This eliminates the need to construct, 
manage and eventually decommission/rehabilitate a separate storage facility. Where separate sludge 
storage is practised, freeze-thaw action assists in the densrfication process. 

Less commonly used, but potentially effective, is the disposal of sludges underground. This procedure 
minimizes the potential for disturbance of the sludges, and also eliminates the need for separate closure 
measures. This practice may be particularly effective for the disposal of sulphide precipitates where 
oxygen regime is critical for sludge stability. 

Sludge recycling for metal recovery may be possible, but economics and chemical characteristics of the 
sludge may preclude this use. The sun/ey of plants identified two waste water treatment systems 
associated with smelters whçre final sludges are recycled to the smelter to recover metals, and eliminate 
off-site disposal. 

9.2 PRACTICES TO CONTROL POLLUTANTS AT SOURCE 

Site mn-off and stormwater management 
Reagent use/process modifications 
Blasting (ammonia control) 

Site Run-off and Stormwater Management 

Sources of site run-off include; direct precipitation, surface watercourses, snow melt and occasionally 

groundwater flows. 

Normally, site run-off is collected in small catchments to allow settling of solids, or (if appropriate) run-off 
can be directed to either mine water or tailings ponds. Where surface runoff is likely to be acidic and/or 
contain dissolved metals, all run-off should be collected and directed to an appropriate treatment facility. 
The design of storage areas for product and waste material should allow containment of all stormwater 
or drainage . In some cases covering or protection of stock piles may be appropriate to minimize the 
effect of storm erosion and to reduce dust transport to other areas. 

Further control of stormwater can be achieved through provision of erosion protection to minimize 
suspended solids loading from catchment and yard areas. Typical erosion protection methods include: 
site grading, revegetation of exposed soils, and crushed stone applications to yard areas. 

BEST MANAGEMENT PRACTICES 9 - 3 



«p/3763-15/sect9.rep/a 

Reagent Use/Process Modifications 

Measures to Improve effluent quality through reagent use and process modifications are typically site 
specific. A number of Ontario gold mills, have been able to reduce by application of cyanide measuring 
systems and process controls, thereby generating an improved effluent. 

The present effluent treatment system employed at the Hemic Gold operation, which is contingent upon 
the use of tailings reclaim solution in the grinding circuit, allowed a reduction In cyanide consumption 
and hence a lower level of cyanide and heavy metals in the effluent to the treatment plant. Residual 
heavy metals contained in the tailings pond reclaimed solution, are apparently adsorbed onto solids in 
the grinding process. See Section 3.1 (Hemlo gold process) for further process details. 

Blasting (Ammonia Control) 

The common explosive used in production mining is the mixture of ammonium nitrate and fuel oil 
(ANFO) containing about 95% of ammonium nitrate. In open pits, and large underground operations, 
bulk loading is practised, otherwise bags may be used. Because exposed ammonium nitrate dissolves 
rapidly in water, the use of ANFO is avoided in drill holes which are wet. ANFO is not used for loading 
upholes nor for small diameter drill holes common to development mining. 

Alternative explosives comprise water-based gels and emulsions which contain 60-80% of ammonium 
nitrate. They are usually supplied in pacl<ages and holes can be loaded mechtanically. For large 
diameter (greater than 3" diameter) holes, bulk emulsions can be employed. The gels and emulsions are 
much less prone to ammonium nitrate dissolution, a typical gel shows dissolution rates 200 times less 
than ANFO, and emulsion at about half of the rate of gels. These explosives detonate with higher 
efficiency and more completely than ANFO. 

Nitroglycerine-based explosives are packaged, contain approximately 40% of ammonium nitrate, and are 
extremely efficient. They are used mainly in development mining. 

Loading of packaged water gel or emulsion explosives takes about twice as long as for ANFO. even 
when pneumatic cartridge loaders are employed. Based on equivalent explosive effect, the material cost 
of water gel or emulsion explosives is approximately five times that of ANFO. Bulk emulsions are 
approximately four times the cost of ANFO, and nitroglycerine-based explosives are about six times the 
cost of ANFO. (Steis T.A., pers. comm.). 



9 - 4 BEST MANAGEMENT PRACTICES 



wp/3763- 1 5/sect9.rep/a 

Given the higher labour and material cost incurred by the use of alternatives to ANFO, it Is not 
economically feasible for production mining operations to use other thian bulk or bagged ANFO. except 
for specific wet areas of the mine or for uphoies and development mining. 

Reduction of ammonium nitrate dissolution and contamination of the mine water, therefore, rests on 
responsible application and handling of ANFO. Basic practice Includes: 

ANFO use to be avoided In wet areas or holes that make water; 

unused ANFO to be returned to the storage area; 

ANFO spillage to be contained and recovered for disposal. 

9.3 RECYCLE 

In-plant and extra-plant recycle is practised at most milling facilities for both gold and base metals. This 
is particularly true of the more modern plants which are designed at the outset with recycle capabilities, 
in-plant recycle includes sources such as: thickener overflows, barren cyanide solution, stripping 
solutions, concentrate dewatering solutions, and spent cooling water. Certain of these sources are 
specific to gold milling operations, and others are more applicable to base metal operations. 

Extra-plant recycle sources include reclaim from tailing and/or polishing ponds, and mine water. Gold 
plants, employing cyanide leaching alone for gold recovery, with certain specific exceptions, and 
depending on process configuration are generally capable of operating at high rates of recycle. A 
specific exception Is where graphite is present in the ore. Graphite has the potential to adsorb dissolved 
gold when present in combination with cyanide solutions. The potential for recycle in such cases is 
consequently limited to solutions which do not contain cyanide, or which contain very low cyanide 
levels. 

The potential for in-plant reclaim at base metal milling operations is generally more restricted than for 
gold mills, because of the greater potential for process fouling by residual flotation reagents. The extent 
to which recycle can be practised from sources exterior to the mill is less restricted. Recycle rates of up 
to 80 - 85% are not uncommon. Generally, fresh water is used for sprays, cooling water, gland seals 
and reagent mixing. In some instances, depending on quality, some exterior reclaim water, from either 
tailings or mine water, can be used for this purpose. Case by case assessments are required. 



BEST MANAGEMENT PRACTICES 9 - 5 



.«p/3763- 1 5/sect9.rep/« 

9.4 OPERATOR TRAINING AND MANAGEMENT STRATEGIES 

Operator training 

Management strategies and procedures 

Operator Training 

The demands on waste water treatment plant operators are becoming increasingly onerous as plant 
systems become more sophisticated. Operators are also required to deal with increasingly complex 
environmental regulations. At several plants, operators with degrees in environmental engineering, or 
similar disciplines, are positioned to oversee treatment systems. Upgrading of qualifications is also 
commonplace, though participation in various conferences and courses. Optimal functioning of BAT 
plants cannot be achieved without the skills of qualified personnel. 

Management Strateoies and Procedures 

Linked to operator training skills, is the need for management strategies and procedures to deal with 
day-to-day operations, and with emergency situations. Management strategies include the 
implementation of: reporting procedures, establishing contingency plans to deal with spills and upsets, 
ensuring that operating and training manuals are available, ensuring that skilled operators are selected 
for key positions, and ensuring that regular performance and compliance audits are performed. 

A number of these activities are mandatory in Ontario, being specified as conditions on certificates of 
approval to operate waste water treatment facilities. 

9.5 BACKFILL OPERATIONS 

Backfill is a term normally used to describe the return of mill tailings solids to underground mine 
workings. The process typically involves a cycloning step in a backfill plant to separate the coarse 
tailings fraction (sand fraction) from the fine fraction (slimes). Alternatively, sand from surface 
geomorphological structures, such as eskers, may be trucked to the mine for use as backfill. At some 
operations crushed waste rock may be used. 

Backfill sands, removed from tailings by cycloning, are directed or pumped underground as a sluny, 
where the sands are allowed to settle out, in order to fill mining working areas no longer in use. 
Frequently, cement is added to the backfill sands to promote stability. Tailings slimes are generally not 
suited to backfilling operations because they fail to achieve sufficient strength on consolidation. Some 
recent innovations in t)ackfill technology have been able to partially overcome this problem. 



9 - 6 BEST MANAGEMENT PRACTICES 



\«p/3763-1b/sect9.rep/a 

The proportion of total mill tailings which can be directed underground, over the life of a mine, varies 
greatly, depending on mining methods, particle size and mineralogical composition. Figures in the order 
of 30 percent are commonplace. 

The most critical factors in determining mine tiackflll needs are the mining methods used and operating 
schedules. Certain mining methods require backfill to retain underground stability. The need for tiackfill 
also varies greatly with the stage of mine development. 

From an overall environmental perspective, backfill operations are advantageous because they reduce 
the requirement for surface storage of tailings solids. However, even if the entire mine could be 100% 
backfilled (which is not feasible with any of the mining methods) there would still be a requirement for 
surface tailings storage. The reason for this is that rock taken from the ground and crushed cannot 
physically be placed back into the same original space, because of the added volume of pore spaces. 

From a BMP perspective, backfill operations (using tailings) impact on the operation of tailings systems 
by reducing ultimate storage volumes, and by increasing water discharge volumes to tailings. This latter 
increase can frequently be offset by reclaim from tailings, depending on site specific circumstances. 



BEST I^ANAGEMENT PRACTICES 9 - 7 



wp/3763- 1 SAabotcon. rep/a 



SECTION 10 
SUMMARY AND CONCLUSIONS 



wp/3763-15/5ect10.rcp/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

10 SUMMARY AND CONCLUSIONS 

10.1 APPROACH TO THE SELECTION OF BAT TECHNOLOGIES 

In reviewing potential BAT level technology trains, applicable to tlie Metal Mining Sector the study team 
has refrained from defining single 'best' technologies for each sub-sector. Rather, with qualification, 
several technology trains are defined which are each capable of achieving effluent wastewater control 
standards equivalent to, or better than, those provided for by US EPA BAT/NSPS standards. This 
approach is in keeping with findings presented in the 1982 US Development Document for Effluent 
Limitation Guidelines and Standards for the Ore Mining and Dressing Point Source - Category adopted 
in the US Code of Federal Regulations No. 40, Part 440 - Ore Mining and Dressing Point Sources 
Category (1989). 

Inclusion of alternative BAT level technologies allows operators the flexibility to address varying site 
conditions, which typify the industry. Most notable, in this regard, are varying geological conditions, 
topographical limitations affecting possible methods of tailings disposal, specifics of metal recovery 
process details and site specific environmental sensitivities. 

BAT level technology trains identified in this report are defined for the gold and base metal subsectors 
only. For iron ore processing operations, suspended solids. pH and total iron levels are the only 
parameters of concern. These are controlled by primary /secondary settling, with occasional use of 
flocculating agents. 

Wastewater control technologies applied to the silver and uranium sectors, excluding those required for 
the control of radionuclides, are not different from those used by gold and base metal subsectors. 

10.2 COMPARISON OF REGULATORY STANDARDS AND APPROACHES 

Ontario metal mining effluent quality guidelines, together with limits placed on recent certificates of 
approval issued to site operations by the OMOE, are compared with those of other jurisdictions in 
Section 4. Generally, limits set out on recent certificates of approval are comparable to Canadian 
Federal regulations, and to those used by the United States and Western Europe. As a standard of 
comparison with MISA objectives. US EPA regulations recognize three categories of performance 

SUMMARY AND CONCLUSIONS 10-1 



AP/3763-1 VscctlO.rep/a 

Standards BPT (best practical control technology), BAT (best available technology economically 
achievable), and NSPS (new source performance standards). Best management practices (BMP) are 
recognized in the 1982 Development Document (referenced above) but are not specified in the 
Regulations, NSPS apply to newly constructed operations, subsequent to 1983. Thirteen subcategories 
of metal producers are defined in the US EPA Regulations. These include all Metal Mining sub-sectors 
as well as other groupings. 

A principal focus of the US EPA regulations is the total elimination (zero volume) of effluent discharge 
from: gold, silver, base metal and uranium mining and milling operations. For base metal and other 
flotation operations this objective pertains to NSPS only. Relief from 'zero volume discharge* is provided 
for facilities located in geographic zones with net annual precipitation. 

In instances where relief from "zero volume discharge' is permitted, maximum feasible recycle Is required 
for gold and silver operations using cyanide leaching, uranium subcategories, and for flotation 
operations (principally base metal concentrators), commissioned subsequent to 1983 

The net annual surplus of precipitation less evaporation in Ontario varies from 200 to 500 mm. As such, 
'zero volume discharge' as practised in drier climates using natural evaporation is not possible in 
Ontario. 'Zero volume discharge" could only be obtained by fuel assisted evaporation of site effluents 
(Appendix F). Pollution abatement in Ontario is consequently focused on parameter concentration 
reduction, and restricting volume discharges to the extent feasible, through recycle and other means. 

Cyanide control requires special consideration, US EPA regulations permit no discharge of cyanide 
waste waters, subject to the 'net precipitation' relief clause. However, there is no specified limit set for 
cyanide in the Federal Regulations. Setting limits for cyanide has therefore fallen, by default, to state 
authorities. At present, there appears to be only one US gold mine which discharges mill waste waters 
to the environment. All other operations are situated in net evaporation areas, principally in the arid 
south and mid-west. 

In the prominent mining areas of northwestern Europe, notably the Scandinavian countries, effluent 
quality standards are set on a case-by-case basis, relative to a set of guidelines. There is no thought, at 
the present time, to move to a set of standard regulatory limits. Germany employs Federal Regulations, 
in conjunction with site specific limits. Metal mining in (West) Germany, is virtually non-existent but a 
member of smelters and refineries treat imported concentrates. 



SUMMARY AND CONCLUSIONS 



wp/3763-15/sect10.r 



Elsewhere, in Australia and New Zealand, conditions vary. Australia imposes regulations at the state 
level. These vary substantially, from state to state. The majority of mining activities are located in arid 
zones. In New Zealand, there are only two relatively new gold mines. Limits are set on a case-by-case 



10.3 PREFERRED BAT LEVEL TECHNOLOGIES 

No attempt is made to select single 'best' technologies, or to rank the technologies, as their application 
is frequently site specific. Varying ore types, available facilities for tailings and settling ponds, recovery 
process specifics and environmental sensitivities are components of the selection process. 

For these same reasons, it must be emphasized that it is not possible to predict the quality of the 
effluent that would result from the application of any BAT option to any particular site without first 
conducting site specific testwork. 

Gold Subsector 

The greatest diversity of BAT level technology trains, selected herein as preferred technologies, are those 
applying to the gold mining/milling subsector. This is principally because of: (1) the complexity of 
cyanide treatment systems, which typically provide combined treatment of cyanide and heavy metals, (2) 
the common association of arsenic with gold deposits, which requires separate treatment from other 
heavy metals, and (3) the extensive research which has gone into the control of gold milling effluents, 
principally because of the above complexities and the substantial cost of effluent treatment. 

Wastewater control technologies applied to the gold subsector in Ontario are as sophisticated and 
varied as any applied throughout the world. The only notable exceptions are the use of chemical 
treatment systems (SC^-Air) for slurries, soon to be employed at Deak Resources' Kerr Mill near Klrkland 
Lake. Ontario, and currently practised at some operations in Quebec. British Columbia, and in the United 
States; and use of sand filtration as an add-on treatment in New Zealand. 

Thirteen technology trains have been identified as being capable of achieving BAT level wastewater 
control for the gold subsector. as described below: 

Conventional technologies for Removal of Suspended Solids. Cyanide and Heavy Metals. 
Natural Degradation (N.D.) (seasonal discharge with two pond system) 
Inco SOj-Air (on slurry) /Tailings Pond/Polishing Pond 
. N.D./INCOSQj /Air/Polishing Pond 

SUMMARY AND CONCLUSIONS 10-3 



wp/3763- 1 5/5ect10.rep/a 

N.D./Hydrogen Peroxide/Polishing Pond 
N.D./INCO SC^ /Air/Clarification 
N.D./Hvdrogen Peroxide/Clarification 

Technologies for the removal ot suspended solids, cyanide and heavy metals, where arsenic is also 
present, are defined as: 

N.D./Hemlo Process/Clarification 

N.D./Ferric Ion Precipitation/Polishing Pond (seasonal discharge with 

two pond system) 

INCO SO^ -Air/Ferric Ion Precipitation/Tailings Pond/Polishing Pond 

N.D. INCO SOj -Air/Ferric Precipitation/Polishing Pond 

N.D./Hydrogen Peroxide/Ferric Precipitation/Polishing Pond 

N.D./INCO SO^ -Air/Ferric Precipitation/Clarification 

N.D./Hydrogen Peroxide/Ferric Precipitation/Clarification 

The last seven technology trains are modifications of the six basic technology trains, specifically adapted 
for add-on control of arsenic (as well as antimony). Four of the 13 technology trains are not presently in 
use, but represent rearrangements of proven technology and therefore could readily be used. 

All of the technology trains presented provide progress toward the MISA objective of virtual elimination 
of toxic compounds, but none of the employed technologies are as yet capable of achieving that 
objective. 

Also, subject to confirmation by MISA and other data sources, application of preferred BAT options is 
likely to enable compliance with toxicity requirements in most cases. Non-lethal effluents are 
demonstrated at a number of specific sites. 

In addition to the 13 technology trains listed above, for cyanide and metals removal, two technology 
trains are also identified for treatment of mine water alone. These are use of a settling pond(s) where 
acid mine drainage is not a factor, and use of a high density sludge hydroxide precipitation plant where 
acid mine drainage requires treatment. The latter case may also include treatment of site area run-off as 
well as mine water. 



10-4 SUMMARY AND CONCLUSIONS 



wp/J/bJ 1b/5ect1().tep/a 

Base metal Subsector 

From investigations Into available BAT level technologies, five teclinology trains have been identified 

being capable of providing suitable treatment for base metal mine effluents. These are defined as: 



Tailings Pond/Hydroxide Precipitation/Secondary Settling 
Tailings Pond/Hydroxide Precipitation/Clarification 
Tailings Pond/Sulphide Precipitation/Clarification, and 
Multistage Precipitation/Multistage Clarification 
Under Water Disposal 



The first two technology trains are standard practice throughout the industry, and are practised In 
Ontario. To be compatible with US EPA NSPS, wastewater recycle is required to the extent feasible with 
these two technology trains. Provision is made in the NSPS to allow partial relief from recycle, where it 
can be demonstrated that process upsets will be linked to higher rates of recycle; and where feasible 
control technologies have been investigated in an attempt to alleviate the anticipated 'fouling' problem. 

The tailings pond/sulphide precipitation/clarification technology train is practised at one mine/mill in 
Sweden and one in British Columbia. The sulphide precipitate in the former case is disposed 
underground with the backfill. In the latter case, it is coprecipitated with the tailings. 

Multistage precipitation/multistage clarification is the most complex and costly of the technology trains 
listed. This method involves sulphide precipitation, as one of its components, and is specifically 
designed for low volume, concentrated waste streams, derived from stand alone smelter/refineries. Its 
current world wide use is limited to selected plants in Germany and Sweden. The sulphide sludge is 
treated as a hazardous waste, and care must be taken to ensure that the sulphide precipitate is not 
exposed to oxygen in the disposal environment; otherwise the sulphide will oxidize to the more soluble 
sulphate. 

Of the various methods of heavy metal precipitation employed within the industry, sulphide precipitation, 
based on theoretical solubilities and limited data available from Europe, appears to be the most effective. 
However, its use within the industry is still essentially limited to specialized instances such as with 
smelter/refineries, and for precipitation of lead, cadmium and other more exotic heavy metals. Definitive 
performance compjarisons between sulphide and hydroxide precipitation are consequently still unclear. 
Care is required for the disposal of sulphide sludges to prevent oxidation to the more soluble sulphate 
condition. 

SUMMARY AND CONCLUSIONS 10-5 



wp/3753-15/5ecn0.rep/a 

Under water lake disposal of massive sulphide tailings is successfully practised by Hudson Bay Mining 
and Smelting in Snow Lake. Manitot)a, and by Cominco at the Polaris Mine in the Northwest Territories. 
Deep sea disposal is practised at Island Copper (British Columbia), and in Norway. Technically, the 
practice is of added value because it works to prevent sulphide oxidation (under properly controlled 
conditions), and therefore limits heavy metal concentrations in the final effluent, as well as facilitating 
mine closure. 

Iron. Silver and Uranium 

Iron mining, as indicated above, primarily involves consideration of suspended solids, pH and soluble 
iron The standard wastewater treatment technology is use of primary (tailings ponds) and secondary 
settling, occasionally with added use of flocculating agents. To our knowledge, no additional or more 
complex technologies are in use. 

Wastewater treatment technologies used to treat effluents from silver and uranium mines/mills are, as 
indicated previously and with the exception of radionuclides, not different from technologies used to 
treat gold and t>ase metal effluents. NSPS for uranium allow relief from 'zero volume discharge' in net 
precipitation areas. 

10.4 BEST MANAGEMENT PRACTISES AND ALTERNATIVE TECHNOLOGIES 

Best management practises in the mining industry focus on: improving efficiency of water use and 
recycle, avoiding and providing contingencies for plant upsets, and controlling underground 
management and use of ammonia based explosives, especially ANFO. Adequate staff training, 
guidance and reporting procedures are also critical to successful operations. 

in the gold industry, optimization of cyanide use in the mill, has improved wastewater quality at some 
operations. This practice can result in substantial cost savings provided that gold recovery is not 
adversely affected. 

Alternative technologies, in the sense described here, apply to alternative processes used for product 
recovery, as opposed to effluent treatment. Treatment of arsenic bearing gold ores is an area where 
significant improvements can be realized by the adoption of hydrometallurgical oxidation of 
concentrates, rather than roasting. 

In concentrating operations, the use of alternative reagents can sometimes improve effluent quality but 
must be evaluated separately for each site and ore type. 

10 - 6 SUMMARY AND CONCLUSIONS 



10.5 NON-LETHALITY AND VIRTUAL ELIMINATION OF PERSISTENT TOXIC CONTAMINANTS 

Toxicity data from OMOE's MISA monitoring program were not available at the time of report 
preparation. Non-lethal effluent have, nevertheless, been demonstrated for a number of Ontario mills 
(both gold and base metal) during routine monitoring. Ontario and British Columbia appear to be at the 
forefront of toxicity testing for mine/mill effluents world wide. Elsewhere, toxicity testing is generally 
quite limited, or non-existent, except where discharge to trout and salmon streams occurs. Most US 
mills achieve 'zero volume discharge' and therefore do not require toxicity testing. 

Subject to future confirmation by MISA and other data sources, and site specific testing, application of 
preferred BAT options (together with BMP), in most cases, is expected to enable compliance with 
toxicity requirements. 

Virtual elimination of persistent toxic contaminants can be achieved through either 'zero volume 
discharge' or through 'zero concentration of contaminants'. Zero volume discharge is not feasible in 
Ontario (see Section 10.2). Zero concentration of contaminants is also not feasible with any of the 
technologies applicable to the Metal Mining Sector. Progress in the reduction of contaminants (i.e. 
progress towards virtual elimination) is made by all of the preferred BAT options defined in Section 7. 
Contaminant reduction achievable by BAT is further enhanced through application of Best Management 
Practice. 



SUMMARY AND CONCLUSIONS 10 - 7 



vvp/3/LJ Mtflatioii,c 



SECTION 11 
REFERENCES AND SELECTED BIBLIOGRAPHY 



wwp/3763-15/5ect1 1 rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

11 REFERENCES AND SELECTED BIBLIOGRAPHY 

11.1 REFERENCES 

1) Fisheries and Environment Canada. 1978. Hydrological Atlas of Canada 

2) Gouvernement du Quebec, Ministère de l'Environment. 1989. Directive No. 019, Industries 
Minières. 

3) INCO Exploration and Technical Services Inc. 1991. The inco SOj-Air Cyanide Destruction Process. 
17 pp. 

4) Jarrett, B.M. 1982. Development Document for Effluent Limitations, Guidelines and Standards for 
the Ore Mining and Dressing Point Source Category. US ERA Report No. 440/1 -82-061 -b. 

5) McNamara, V.M. 1989. The AVR Process for Cyanide Recovery, and Cyanogen Control for Barren 
Recycle and Barren Bleed, in: Gold Mining Effluent Treatment Seminar. March 22-23, 1989, 
Mississauga, Ontario. Environment Canada. 

6) Mining Journal, London. 1991. Mining Annual Review. 292 pp. 

7) Mohanta, S., J. Jacobs, I. Kennedy, B. Fleet and S. Das Gupta (HSA Reactors Ltd.). 1980. Pilot 
Plant Investigations of a Novel Electrochemical Treatment of Effluents from Gold Milling Processes. 
Prepared for the Department of Supply & Services Ottawa. Canada. 108 pp. 

8) Northern Miner Press Ltd. 1970. American Mines Handbook 1990. 312 pp. 

9) Northern Miner Press Ltd. 1991. Canadian Mines Handbook 1991 - 92. 536 pp. 

10) Ontario Ministry of the Environment. 1981. Guidelines for Control in the Ontario Mineral Industry. 
27 pp. 

REFERENCES AND SELECTED BIBLIOGRAPHY 11-1 



wp/3/fa'J i5/'j«;ctt 1. rep/a 

11) Ontario Ministry of the Environment. 1984. Water Management. Goals, Policies, Objectives arxJ 
Implementation Procedures of the Ministry of the Environment. Revised May 1984. 

12) Ontario Ministry of the Environment. 1991. MISA Monitoring Database Guide Draft Version 1. 

13) Simovic. L and W.J Snodgrass. 1989. Tailings Pond Design for Cyanide Control at Gold Mills 
Using Natural Degradation, jn: Gold Mining Effluent Treatment Seminar, March 22-23, 1989. 
Mississauga, Ontario. Environment Canada. 

14) Steis, T.A. Manager. Technical Resources Explosives, ICI Explosives Canada (Personal 
communication). 

11.2 SELECTED BIBLIOGRAPHY 

1) Burns and Roe Construction Corporation. 1974. Evaluation of Ion Exchange Processes for 
Treatment of Mine Drainage Waters. National Technical Information Service. U.S. Department of 
Commerce. PB-227-734. 183 pp. 

2) Degussa Canada Ltd. 1991. Cyanide Destruction Technology Operations Overview. Prepared for 
Ontario Ministry of the Environment. 

3) Environment Canada. 1984. Ammonium Nitrate. ENVI RO Technical Information for Problem Spills. 
74 pp. 

4) Environment Canada. 1987. Environmental Aspects of Nickel Production, Sulphide Pyrometallurgy 
and Nickel Refining. Report EPS 2/MM/2. 121 pp 

5) Environment Canada. 1987. Mine and Mill Wastewater Treatment. Report EPS 2/MM/3. 72 pp. 

6) Environment Canada. 1987. Mine and Mill Wastewater Treatment Report EPS 2/MM/3. 86 pp 

7) Environment Canada. 1988. Status Report on Water Pollution Control in the Canadian Metal Mining 
Industry (1986). Report EPS 1 /MM/3. 27pp. 

8) Environment Canada/Ontario Mining Association. 1989 Gold Mining Effluent Treatment Seminar. 
March 22-23, 1989. Mississauga, Ontario. 



REFERENCES AND SELECTED BIBLIOGRAPHY 



v«p/3763-15/sect11 rep/a 



9) Gilmore. A. 1976. The Ion Exchange Removal of Cyanide from Gold Mill Wastes for Environmental 
Benefit. CANMET Report MRP/MSL 76-26IR. Energy Mines and Resources. Ottawa, Ontario. 

10) Gupta, M.K. 1974. Development of a High Product Water Recovery System for the Treatment of 
Acid Mine Drainage by Reverse Osmosis. National Technical Information Service, U.S. Department 
of Commerce. PB-230 756. 50 pp. 

11) Ingles. J. and J.S. Scott. 1987. State-of-the-Art of Processes for the Treatment of Gold Mill 
Effluents. Environment Canada, Ottawa. Ontario. 

12) Krause, E. and V.A. Ettel. 1985. Ferric Arsenate Compounds - Are they Environmentally Safe? 
Solubilities of Basic Ferric Arsenates. \n: CIM Metallurgical Society Conference on Impurity Control 
and Disposal. Vancouver. British Columbia. 

13) Metcalf and Eddy. Inc. 1979. Wastewater Engineering: Treatment. Disposal, Reuse. Revised by G . 
Tchotjanogious. McGraw-Hill Book Co.. New York. 920 pp. 

14) Randol Gold Forum. Squaw Valley 1990. Randoi International Ltd. 362 pp. 

15) Randol Gold Forum. Cairns 1991. Randol International Ltd. 420 pp. 

16) Scott, J.S. 1987. Waste Management Practices in the Canadian Gold Mining Industry. Canadian 
Engineering Centennial Convention, Montreal, Quebec. 

17) US EPA. 1973. Processes, Procedures, and Methods to Control Pollution From Mining Activities. 
EPA-430/9-73-011: NTIS, US Department of Commerce PB 257-297. 

18) US EPA. 1980. Treatability Manual. Volume III. Technologies for Control/Removal of Pollutants. 
EPA-600/8-80-042 C; NTIS, US Department of Commerce. PB80-223076. 

19) VHB Research and Consulting Inc. and CH2M Hill Engineering Ltd. 1991. Water Pollution 
Abatement Technology and Cost Study. Prepared for Socio-economic Section, Policy and Planning 
Branch. Ontario Ministry of the Environment. PIBS 1549. 



REFERENCES AND SELECTED BIBLIOGRAPHY 11-3 



wp/3763 15/sect11.rep/« 

20) Wasserlauf. MA 1985. Description of Wastewater Treatment Plants at Seven Mining and 
Metallurgical Operations in Eastern Canada Environment Canada. Ottawa. Ontario 

21) Weir. D.R. and R.M.G.S. Berezowslcy. 1987 Aqueous Pressure Oxidation of Refractory Gold 
Feedstocks, jn: International Symposium on Gold Metallurgy at the 26th Annual Conference of 
Metallurgists of the Canadian Institute of Mining and Metallurgy, Winnipeg, Manitoba. 

22) Whitlock, J.L 1987. Performance of the Homestake Mining Company Biological Cyanide 
Degradation Wastewater Treatment Plant, August 1984 - August 1986. jn: SME Annual Meeting, 
Denver, Colorado - February 24 - 27. 6 pp. 



REFERENCES AND SELECTED BIBUOGRAPHY 



wp/3 763 ISAûDotcon. rep/a 



APPENDIX A 
UST OF CANADIAN MINES, MILLS AND SMELTERS 



wp/3763 yb/nin)rn(Hnarrç}/a 



ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

APPENDIX A - LIST OF CANADIAN MINES. MILLS AND SMELTERS 



Legend 



YES 



NO 



M - data obtained from MISA reports, sypplemented whre approprite by follow-up contacts, and study 

team knowledge of operations 



APPENDIX A - UST OF CANADIAN MINES. MILLS AND SMELTERS A.A - 1 



3 3 

O O 

O) Ol 

o o 

3 3 











































1 




o 






















































































z 


Z 


z 


>- 


z 


z 


z 


z 


Z 


z 


z 


z 


> 


> 




>- 


> 




>- 












































s 


> 


>- 


>- 


>- 


> 


>■ 


> 


z 


>- 


z 


z 


>- 


> 


> 




>- 


>• 




> 






















t 
























o 










































s 


1 


1 


■§ 


■g 


■g 


■g 


■g 


■g 


s. 


■g 


^ 


■g 




1 




"g 


"g 








z 




3 


3 


3 


3 


3 


3 


3 


Q 


3 


3 


3 






3 


3 




= 




s 


o 


2 




O 


o 


O 


O 


O 


1 


O 


o 


O 


o 


g 




o 


2 




Q- 




u. 


O) 


B» 


O) 


o> 


o> 


O) 


g» 


o> 


O) 


g> 


g> 


§ 


o> 




? 


? 




l 




o 




o 












(D 




0) 














1 




O. 


tn 




■g 


1 


■g 


■g 


■g 


"g 


■g 




O» 




■g 


■g 




3 




■g 




o 


1 


1 


3 


3 


^ 


^ 


^ 


^ 


^ 


^ 


1 


^ 


^ 


^ 






^ 


^ 






S 




















3 






















I 


















































































o 


p 








































1 










































3 


t> 


§ 


g 


g 


s 




g 


S 


S 


S 


s 


WJ 


C4 


s 


8 




s 


1 




8 




1 


c^ 


J^t 


CM 


"^ 


- 


- 


(0 


r* 


^. 




N 


«• 


^. 


CO 
CO 




CM 




j^. 




g 










































o 










































^ 






















































o 




2 




































1 


c 




c 




































s 


s 




S 


























i 

s 


1 


e 

i 


1 


c 

1 


o 
m 

5 
1 


i 

> 

1 

d 


1 


1 


i 


1 


S 


c 
o 

>. 

o 


l 

1 

1 


1 

1 


1 


S 

o 


1 
1 

o 


1 


1 

m 



c 

8 



OS 

U 

Q Z 

o o 



s 

I 

55 

Î 







z 




> 




s 


s 


z 






z 




> 




>■ 


> 


>- 






? 






















1 




1 


g 


i 










S* 




o> 


p 


p 




















ffi 








g 




J! 


? 


? 


z 








3 




3 


3 


3 


s 


















o 


















a: 


















F 


















t 




















in 




i 




1 


g 


i 










N 




<M- 






























tu 


















p 










c 








QE 






c 




M 






i 


1 






1 


S 


5 




1 


1 


1 


J< 


i 


i 

O 


i 
1 


1 




^ 


o 


^ 


C 


^ 


"% 


^ 


c 




' 


_^ 


_^ 


_^ 


o 


_^ 


i' 


5 





1 




>- 




z 


> 




>- 




2 




>- 


>- 




























S 




> 




> 


>- 




> 




>- 




> 


> 




























— 


■^ 














a. 












a 


o. 




1 










c 




















? 




1 


Q. 




? 




? 




a 


Ô. 












o 












Q 


o 


v> 


ë 




1 




1 


1 




1 




1 




1 


1 


UJ 


UJ 






c 


O) 




c 




: 




o> 


o> 


z 


E 




3 




13 


« 




3 




3 




o 


o 


s 










^ 












■g 


^ 


§ 












3 












^ 


=" 


1 




























^ 




























o J 




g 




« 


i 




1 




S 




g 


i 












6 


CO 




CM 








« 






Q Z 




^ 
























i& 








































» 




























rr 




























Q 












1 




1 


1 


i 

c 

1 


1 


1 


i 

1 


^ 


1 

1 


< 


1 


t 


1 

s 
2 


s 

o 

1 

i 



















> 


>- 




z 






>- 


>■ 




> 
























, 






t 


t 




g 






c 


c 




□> 


















Q, 


Q. 




q> 


Hi 




o 


o 




■g 


Z 










3 


2 












O 












SE 
























' 




1 


i 




g 






<D 






CO 












c 












o 




Q 








■5) 




^ 


C 










1 


f 


} 


ë 


Ô 
i 




_^ 


_^ 


— 


o 


< 



I 



I 



iç 



Q Z 

op 



O U) 



— 





— 
















Q 
















ë 
















i 




2 


>• 


z 


z 


> 




i 




>■ 


> 


> 


>■ 


>- 












1 








o 
















s 




1 


? 


1 


■g 


•g 










3 










s 




o 


2 


1 


o 


o 












o> 




i 


è 




1 


1 


Q. 


îT 


o 


s 


^ 




3 


3 


§ 


= 


=^ 


g 










^ 






{^ 
















^ 
















8 
















1 

: 
c 
















o J 




1 

CO 


g 


|C 


^ 


1 




o o 
















£t 
















Ui 














1 


z 




S 


O 


o 


g 






s 




i 


1 


1 


« 










3 


5 


© 


> 


o 








Ê 




w 


Q 


1 






o 


S 


J 


i 


g 


s 




i 


i 


i 


i 


1 


1 



CANADIAN SMELTERS AND REHNERIES 
LEAD/ZINC 



PLANT 


PRODUCTION 
(TONS/YEAR) 


SMELTER/REHNERY 


CONTACTED 1 


BRUNSWICK MINING AND 
SMELTING, NB 


70,000 


LEAD SMELTER 


N 


CANADIAN ELECTROLYTIC 
ZINC, PQ 


230,000 


ZINC REFINERY 


N 


COMINCO LTD. TRAIL 
OPERATIONS, BC 


15,000-Pb 
300,000-Zn 


ZINC-LEAD-SILVER 
SMELTER/REFINERY 


Y 


KIDD CREEK DIVISION, ON 


130,000 


ZINC REFINERY 


M 


HUDSON BAY M & S 
FLIN FLON, MB 


93,000 


ZINC REFINERY 


Y 



CANADIAN SMELTERS AND RERNERIES 
NICKEL/COPPER 



PUWT 


PRODUCnON 


SMELTER/RERNERY 


CONTACTED 




(TONS/YEAR) 


FALCONBRIDGE 
OPERATION, ON 


600,000 


NICKEL-COPPER 
SMELTER 


M 


HUDSON BAY M & S 
FLIN FLON, MB 


350,000 


COPPER 
SMELTER 


Y 


COPPER CUFF 
COMPLEX. ON 


1,800,000 


COPPER-NICKEL 
SMELTER/REFINERY 


M 


INCO 

PORT COLBORNE, ON 


- 


NICKEL 
REFINERY 


M 


INCO 
THOMPSON, MB 


600,000/55,000 


NICKEL-COPPER 
SMELTER/REFINERY 


Y 


NORANDA 

CCR DIVISION, PQ 


350,000 


COPPER 
REFINERY 


N 


NORANDA 

GASPE DIVISION, PQ 


210,000 


COPPER 
SMELTER 


N 


NORANDA ROUYN 
NORANDA, PQ 


930,000 


COPPER 
SMELTER 


N 


SHERRITT GORDON 
LTD.,AB 


27,000 


NICKEL 
REFINERY 


N 



wp/3763-15Aobotcon.r 



APPENDIX B 
LIST OF UNITED STATES MINES, MILLS AND SMELTERS 



wp/3r63 1 VappendlxB rep/« 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

APPENDIX B - LIST OF UNITED STATES MINES. MILLS AND SMELTERS 

Legend 

Y - YES 

N - NO 

n/a - not applicable 



APPENDIX B - UST OF UNITED STATES MINES. MILLS AND SMELTERS A.B - 1 





1 












































1 




2 


z 


z 




z 


z 


z 


z 


Z 




z. 


Z 


z 


>■ 


Z 


>■ 


z 


>■ 


Z 




i 




z 


z 


>- 




>- 


> 


>- 


> 


> 




>■ 


> 


> 


>- 


>- 


>- 


>-. 


> 


> 






















£ 
























i 








s 






1 




? 


1 




s 


S 


s 




i 




1 


y 


y 




1 




w 


o 


s 




g 


Q. 


t 




s 




I 


1 


1 


?. 


1 


t 


t 


§ 


o 




ë 




Ê 


1 






t 




1 


1 


t 




JC 




Q. 


1 


i 


1 


1 


1 


1 


« 


t 








1 
o 






1 




3 


c 

1 




1 

o 


1 
o 


1 




1 




1 


"" 


"" 


3 












































9 










































— 


p 








































C 












































1 


1 










































I) 


^ 






§ 


1 




g 


§ 


8 


1 


i 




§ 


§ 


§ 


S 


§ 


S 


i 


I 




1 


g 






^- 


CM 




s 




CM 




? 




r- 




O 


«. 




" 


CM 








1 




























































9- 












































5 
































o 












2 










1 


















^ 




■c 












o 










o 


O 












e 




1 




^ 












? 










^ 


= 












= 




S 




CL 

i 

■c 

CO 

s 

1 

z 


1 


1 


1 


— 
5 

c 


i 


f 


i 

u 




o 


o 

c 

s 


1 

M 

5 


1 


s 

-3 


i 
1 

i 


1 

c 


S 


1 


S 



il 

2 S 



§1 



I ï 

i 2 

s CL 

I I 

3 O 

8 8 





1 




Z 


Z 


z 


z 


z 


z 


z 


z 


z 


z 


z 


z 


Z 


z 


z 


z 


z 


z 


z 












































i 




>■ 


> 


> 


>■ 


>- 


>• 


> 


> 


>- 


>■ 


> 


> 


>- 


> 


> 


> 


> 


> 










1 






£ 


£ 


























1 






z 








1 


1 


1 




1 


1 


1 


1 


1 


1 


1 




1 








z 


s 


Q. 


«. 




a 


a 


Q. 


2: 


Q. 


Q. 


Q. 


ca. 


a. 


a 


a 


s: 


a 


*. 


a 






â 


a 


S 


Q. 


o 


S 


S 


S 


a 


S 


S 


S 


S 


S 


S 


S 


a 


S 


Q. 


S 







s 


1 

O 


x: 
1 


1 


a. 


£ 

1 


■c 
1 


1 


1 


£ 

1 


£ 
1 


£ 

1 


£ 

t 


£ 
t 






1 


1 


1 




£ 
1 


1 




s. 




c 






c 


c 


c 




C 


C 


c 


c 


C 


C 


c 




C 




g 










a> 






o 


o 


â 
















<D 


â 







e 








Vi 


fm 




a 






a 


a 




a 


a 


a 


a 


a 


0. 




a 




n 




z 






o 






O 


O 


o 





































â 












































9 












































§ 


J 










































i 


1 










































Q 


1 




1 


1 


1 


« 




1 


1 


1 


1 


1 


1 





i 


1 


eo 


i. 


1 


1 


1 


5 




'" 


^* 








^ 






CN 




^ 


CM 




^" 














1 





















































































































c 


















Q- 


























i 


















Q 


























a 


















6 


























3 


















>. 


























g 
















S 


1 
1 


s 

i 
Î 


, 


1 


1 

c 

1 


S 

>> 


j 




c 

i 


i 

S 
C 


z 


i 


1 


i 


<3 





c 

i 


S 
1 


1 


1 


1 


s 

i 






« 




2 


c 


« 


§ 


5 


« 


s 


1 





T 


^ 


1 


■S 


1 


1 


î 


S 


X 






;t 


S 


— 


c 


M 


J 


« 


5 


t 


"g 


9 


« 


5 





~ 


s 


tj 


S 


5 


s 






= 


3 
CD 


â 


5 


(3 




8 


^ 


<s 


^ 


S 


5 


2 

LU 


tu 


^ 


£ 


A 


b 


1 


^ 



s.. 

3 S- 

2S 

9 

3 



S 5 





P 












§ 




>- 




> 




^ 












8 










d 




> 




> 




s 










g 




1 




■O 




z 




9- 




c 




s 




S 




o 




ë 




JZ 

«- 




« 








•5. 




? 


UJ 


E 




c 




3 


z 






O 






â 












î 






















Zj 












(ô 


p 










i 


i 










< 


2 










^ 


ê 




S 




S 


ë 


o 




CO 




t^ 




f 














9 












ç 












i 












o 












■o 








UJ 




K 








i 


^ 


1 












•8 




^ 






j^ 


« 




3 






° 


O 




O 






i 


1 


1 


m 





! 




> 


> 




> 




> 


>- 




















i 




> 


>■ 




> 




> 


> 
























z 






ID 




■o 




TJ 


TJ 










C 




c 




C 


C 
























s 






O 




o 




O 


o 




11 














o> 


O) 




O 




8 


» 




» 




a> 


V 








o 


S 








? 




tf) 


Ï 






3 




^ 




3 


=^ 


Ul 




















z 




















s 




















o 




















z 






















f 


















^ 


§ 


















§ 


t 




^ 


^ 




s 






o 


z 




in 


O) 




p 






o 
























1 
















































t; 




















§^ 




















£ 




o 
















v 




(Q 
















Q. 




<P 
















«8 




^ 


o 




ë 






o 




1 




> 






* 






c 




m 




C 


p 








o 


y 




o 




"O 










c 


« 




S 


Ml 


Q 


^ 








? 


^ 


w 


u 


o 


« 






1 


E 


J 


I 


2 


i 


Ûj 


c 
o 

1- 





1 






















> 






> 


z 


> 


> 




















3 




> 




> 


>• 


>■ 


> 


> 




? 
















ë 




Z 




■o 




? 


? 


? 


? 


8 




= 








3 












S 




o 




2 


o 


o 


o 


c 




u. 




O) 




o» 


O) 


O) 


o> 


3 




O 




4) 




a> 


a 


o 


o 


s 








•Q 






■a 


■Q 


•Q 


Ol 














c 








ÎS 


P 




^ 




^ 


3 


3 


3 


1 


z 




















s 




















1 




















P 


















W 




















ë 


1 


















^ 


P 


















1 


t 










§ 

CO 


1 


îif 


£.5 
1 1 


3 


£ 
















SSf 
















O 
































o 








ï 












O 
















1 




je 




i 




1 












m 




«S 




o 


^ 










s 






r 


a> 




c 






Q 






^ 


= 


o! 




3 






1 


3 
-1 


i 


i 

oc 
o 




1 
i 


! 


■s 



UNITED STATES SMELTERS/REHNERIES 
LEAD/ZINC 



LOCATION 


PRODUCTION 
(TONS/YEAR) 


SMELTER/RERNERY 


CONTACTED 


East Helena, MT 


70,000 


Lead Smelter 


Y 


Glover, MO 


110,000 


Lead Smelter/Refinery 


N 


Hillsboro, IL 


23,000 


Smelter 


Y 


Doe Run, MO 


225,000 


Lead Smelter/Refinery 


Y 


Jersey Minière Zinc, TN 


90,000 


Zinc Refinery 


N 


Zinc Corporation of 
America, OK 


55,000/55,000 


Smelter/Zinc Refinery 


Y 


Omaha Refinery, NE 


156,000 


Lead Refinery 


N 



UNITED STATES SMELTER/REHNERIES 
COPPER/NICKEL 



PLANT 


PRODUCTION 
TONS/YEAR 


SMELTER/RERNERY 


CONTACTED 


Cerro Copper, IL 


50,000/46,000 


Copper Smelter/Refinery 


Y 


Cyprus Miami Mining, AZ 


450 


Copper Smelter 


Y 


Kennecott, UT 


220,000/228,000 


Copper Smelter/Refinery 


Y 


San Manuel Division, AZ 


300,000/300,000 


Copper Smelter/Refinery 


N 


Chino Mines, NM 


549,000 


Copper Smelter 


Y 


El Paso Refinery, TX 


420,000 


Copper Refinery 


Y 


Hidalgo Smelter, NM 


. 


Copper Smelter 


N 


Reading Metals Refinery, PA 


18,000 


Copper Refinery 


N 


M.A. Hanna, OR 


11,750 


Nickel Smelter 


Y 



>*p/3763-15/l«bolcon.rep/a 



APPENDIX C 
CONTACT LIST - WORLD WIDE OPERATIONS AND AGENCIES OUTSIDE NORTH AMERICA 



wp/3763-15/appendlxc. rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

APPENDIX C 
CONTACT LIST - WORLDWIDE OPERATIONS AND AGENCIES OUTSIDE NORTH AMERICA 

EUROPEAN COMMUNITY: 

Delegation of the Commission of the European Communities. Suite 1110. 350 Sparks St., Ottawa. 
Contact person: M. Jil Courtice. 

NORWAY: 

State Pollution Control Authority. P.O. Box 8100 Dep.. 0032 Oslo 1, Stromsveien 96. 
Contact persons: Sir! Sorteberg, Kari Kjenigsen. 

SWEDEN: 

Boliden Mineral AB. S-936 00 Boliden. 

Contact persons: M. Per G. Broman, VP Environment and M. Torbjorn Goransson. 

Canadian Embassy. P.O. Box 16129. S-103 23 Stockholm. 
Contact person: M. Claes Bonde, Technology Development Officer. 

Statens Naturvardsverk. Swedish Environmental Protection Agency. S-171 85 Solna. 
Contact persons: M. Niclas Svenningsen. Principal Technical Officer and M. Lars Lindahl. 

Vielle-Montagne. 590 42 Zinkgruvan. 
Contact person: M. Fred Mellberg. 

FINLAND: 

National Board of Waters and Environment. Industrial Waste Water Office. PB 250 00101 Helsinki. 

Finland. 

Contact person: Emelie Enckell-Sarkola 

Outokumpu Mines Ltd.. Suite 4650. 1 First Canadian Place. P.O. Box 360, Toronto, Ontario. 
Canada M5X1E1. 

WORLD WIDE OPERATIONS AND AGENCIES OUTSIDE NORTH AMERICA A.C - 1 



wB/3763-15/appendlxc. rep/a 

Technical Research Centre of Finland, Laboratory of Mineral Processing. TutkiJanlcatuI, SF 83500 

Outokumpu. Finland. 

Contact person: Prof. Risto Rinne. 

GERMANY: 

Canadian Embassy. Wissenschaft und Technologie, Friedrlch-Wilhelm-Str. 18. D-5300 Bonn 1. 

Contact person: Dr. Bruno Wiest, Officer Technology Development. 

Preussag Noell, Wassertechnik GmbH, NL Hannover, Heinrich Hertz-StraBe 23, 3005 Hemmingen 1. 
Contact person: Herrn Dr. Roennefahrt. 

Nord Deutsche Affinerie, P.F. 309362, 2000 Hamburg 63. 
Contact person: Herrn. Dr. Veitan. 

Preussach A. Geselshaft, Metaleurope, Nordenham. 
Contact person; Herrn. Voff, President 

Working Group Dr. Kroll. 

ENGLAND: 

Carnon Consolidated Ltd.. P.O. Box 2 Baldhu, Truro. Cornwall. 
Contact person: M. Gary Ljeun, Assistant Mill Superintendent. 

British Mining Consultants Ltd., P.O. Box 18, Mill Lane, Huthwaite, Sutton-in-Ashfield, Nottinghamshire 

NG17 2NS. 

Contact person: M.J.B. Lott Managing Director. 

Her Majesty's Inspectorate of Pollution (HMIP), Department of Energy. 
Contact person: M. Paul Hudson. 

University of Liverpool. Dr Mike Johnson. 

Mining Association of the United Kingdom, London. 
Contact person: G.C. Uoyd Davis, Secretary. 



AC - 2 WORLDWIDE OPERATIONS AND AGENCIES OUTSIDE NORTH AMERICA 



vyp/3763- 1 5/»ppendlxc.rep/a 

FRANCE: 

Ministère de l'industrie et de l'Aménagement du Territoire, Direction Générale de l'Energie et des 
Matières Premieres, 101 rue de Grenelle 75700 Paris. Cedex. 
Contact person: Catherine Châtelain. 

Lonmines. Contact person: B. Marrel. 

Département Mineralurgie - DAM/MIN, Av. de Concyr - BP 6009 - 45060 Oiieans Cedex 2. 
Contact person: Jean Libaude. 

ITALY: 

Agip Minière, 20139 Milano, 

Contact person: M. Ugo Andolfato, Manager, Foreign Mining Activities. 

AUSTRALIA AND NEW ZEALAND: 

Australian Trade Commission, 175 Bloor St. East, Suite 318, Toronto, Ontario, M4W 3R8. Contact 
person: Mr. Terry Hunt, Senior Trade Commissioner. 

University of South Australia, Gartrell School of Mining, Metallurgy and Applied Geology. 
Contact person: John Eliott. 

Ministry of Commerce, Box 1473, Wellington, New Zealand. 
Contact person: Cathie MacKenzie. 

Peter J. Lewis and Associates Pty Ltd, 47A Burlington Street, Crows Nest, NSW. 2065 
Contact Person: Peter Lewis 

Waihi Gold Mining Company Ltd., P.O. Box 190, Waihi. New Zealand. 
Contact Person: Richard Carlton 

BELGIUM: 

Métallurgie IHoboken - Overpelt N V, Adolf Greinerstraat 14. B-2710 Antwerpen, Belgium. 
Contact person: Willi Gronckhaarh. 



WORLD WIDE OPERATIONS AND AGENCIES OUTSIDE NORTH AMERICA A.C - 3 



wp/3re3i5/appendlxc. rep/a 

JAPAN: 

Japan External Trade Association, JETRO. 151 Bloor St. West, Suite 700, Toronto, Ontario. M5S 1T7. 

Contact person: Ms. Sharmila Mohare. Energy and Teclinoiogy. 

SOUTH AFRICA: 

GENMIN, Unicorn House, 70 Marshall St.. Johannesburg. 2001 P.O. Box 61820, Marshalltown 2107. 

Repulic of South Africa. 

Contact person: Dr. A.IC Haines. Chief Executive, Minerals Technology. 



AC - 4 WORLDWIDE OPERATIONS AND AGENCIES OUTSIDE NORTH AMERICA 



wp^}763-1 5Aabolcon.rep/« 



APPENDIX D 
GLOSSARY 



ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

APPENDIX D - GLOSSARY 

acid mine drainage 

Acidic run-off water from mine waste dumps and mill tailings ponds containing sulphide minerais. Also 
refers to ground water pumped to surface from mines. Such drainage often requires treatment to buffer 
acidity before it can be released into the natural environment. 

activated carbon 

Granular or fine carbon which has been regenerated through heating in the absence of oxygen, to 
restore adsorption characteristics. 

adsorption 

The adherence of dissolved, colloidal, or finely divided solids on the surface of solids with which they are 
brought into contact. 

ANFO 

Acronym for ammonium nitrate and fuel oil, a mixture used as a blasting agent in many mines. 

arsenopyrite 

An iron sulphide mineral containing arsenic (FeAsS) 

autoclave 

A strong vessel or chamber suitable for high temperature, high pressure chemical reactions used to treat 
refractory ores (see pressure oxidation). 

azurite 

A blue carbonate of copper, 0113(00^ )2(OH)2, crystallizing in the monoclinic system. Found as an 
alteration product of chalcopyrite and other sulphide ores of copper in the upper oxidized zones of 
mineral veins. 



APPENDIX D - GLOSSARY A.D - 1 



wp/3763-15/appendlxd.rep/a 

backfill 

Waste material used to fill the void created by mining an orebody 

backwashing 

method used to clean granular filtration beds, wherein water is forced, under pressure, in the opposite 
direction of the normal filtrate path. 

BADT 

Acronym for Best Available Demonstrated Technology used by the US EPA to set NSPS. 

basic ferric arsenate 

Precipitates from an Fe (lll)/As (V) solution, produced using either NaOH or Ca(OH)2. 

BAT 

Acronym for Best Available pollution control Technology, and defined by OMOE as a combination of 
demonstrated treatment technologies and in-plant controls, applicable in the case of this report to the 
Metal Mining Sector; in the US-ERA system used to define Best Available Technology Economically 
Achievable, 

beneficiation 

a) The dressing or processing of ores for the purpose of (1) regulating the size of a desired product, (2) 
removing unwanted consituents, and (3) improving the quality, purity, assay grade of a desired product; 

b) Concentration of other preparation of ore for smelting by drying, flotation, or magnetic separation. 

BMP 

Acronym for Best Management Practice. 

BPT 

Acronym for Best Practiced Technology Currently Available used by the US EPA. 

bullion 

Metal in bars, ingots or other uncoined forms, 

CANMET 

Acronym for the Canada Centre for Mineral and Energy Technology. 

AD - 2 APPENDIX D - GLOSSARY 



wp/J7bJ-lS/ttppend(»d.rep/a 

carbon-in-leach 

A process similar to carbon-in-pulp (CIP). except that carbon is added during the cyanide leach phase, 
rather than following the leach phase (as with CIP), particularly suited to the recovery of gold from ores 
containing graphite. 

carbon-in-pulp 

A process which mixes a cyanide-rich pulp with granulated activated carbon. The gold in solution is 
adsorbed on to the carbon. The carbon is screened and the recovered granules are washed with hot 
sodium hydroxide and sodium cyanide solution to liberate the gold. 

catchment area 

Watershed, generally used in reference to either tailings ponds or surface run-off. 

chalcocite 

Copper sulphide, Ci^S. 

chalcopyrite 

A sulphide mineral of copper and iron. A common ore mineral of copper. 

CIL 

Acronym for carbon-in-Jeach gold recovery from cyanide slurries. 

CIP 

Acronym forçarbon-jn-£ulp gold recovery from cyanide slurries. 

Acronym for weak acid dissociable cyanide, referring to a laboratory technique for measuring free 
cyanide and cyanide associated with weakly bound metallocyanide complexes. 

coagulation 

The binding of individual particles to form floes or agglomerates and thus increase their rate of 
settlement in water or other liquid (see also flocculate). 



APPENDIX D - GLOSSARY A.D - 3 



wp/3763-1 5/appendlxd.fep/a 

concentrate 

A fine, powdety product of the milling process containing valuable metal and from which most of the 
waste material in the ore has been eliminated and discarded as tailings. 

concentrator 

A milling plant that produces a concentrate of the valuable minerals or metals. Further treatment Is 
required to recover the pure metal. 

conglomerate 

A sedimentary rock consisting of rounded, w/ater-worn pebbles or boulders cemented into a solid mass. 

cyanidation 

The process of extracting exposed gold or silver grains from crushed or ground ore by dissolving it in a 

weak solution of either sodium cyanide or calcium cyanide. 

demonstrated treatment technology 

A technology for which data are available and that data can be used to predict, with a reasonable 
degree of confidence, the reliability of the technology and the performance of the technology with 
respect to contaminant reductions and effluent variability at any plant in the sector or sub-sector, given 
the expected variability between plants and could be successfully retrofitted into existing facilities with a 
reasonable degree of confidence. 

disseminated 

A scattered distribution of generally fine-grained metal-bearing minerals throughout a rock body 

dolomite 

a sedimentary rock consisting of calcium magnesium carbonate 

EAG 

Acronym for The Environmental Applications Group Ltd. 

effluent 

Any liquid and associated material discharged, directly or indirectly, to a surface watercourse. 



A.D - 4 APPENDIX D - GLOSSARY 



wp/3763-15/appendl«(l.rep/a 

effluent guideline 

A suggested limit on effluent parameter concentrations. 

effluent technology train 

The sequential use of technologies to produce a desired effluent treatment. 

electrolysis 

A method of breaking down a compound either in its natural form or in solution by passing an electric 
current through it. 

eluate 

A solution obtained by the process of eluation which involves the removal of adsorbed elements by 
washing. 

filter cake 

Wet solids residue remaining after a slurry has been filtered using disc, drum or other mechanical 
filtering equipment. 

flocculant 

An agent that induces or promotes flocculation or produces fioccules or other aggregate formation, 
especially in clays and soils. 

flotation 

A milling process by which some mineral particles suspended in water are induced to become attached 
to bubbles and float, and others to sinl<. In this way the valuable minerals are concentrated and 
separated from the worthless gangue. 

frother(s) 

Sustances used in flotation processes to make air bubbles sufficiently permanent principally by reducing 

surface tension. Common frothers are pine oil, cresylic acid, and amyl alcohol. 

galena 

A sulphide mineral of lead, being a common lead ore mineral. 



APPENDIX D - GLOSSARY A.D - 5 



wp/3 763-1 5/appendlxd. rep/a 

generic effluent technology train 

Effluent technology trains which may or may not be in current use, but could be used based on existing 

technology components used within the Metal Mining Sector. 

gravity separation 

Treatment of mineral particles which exploits differences t)etween their specific gravities. Their sizes and 
shapes also play a minor part in separation. Perfomned by means of jigs, classifiers, hydrocyclones, 
dense media, shaking tables, Humphreys spirals, sluices, and vanners. 

heap leaching 

A process whereby valuable metals (usually gold, silver and copper) are leached from a heap, or pad, of 
crushed ore by leaching solutions percolating down through the heap and are collected from a sloping, 
impermeable liner below the pad. Very popular in the southwestern U.S. 

heavy-media separation 

Also known as the sink-float process, this separation technique employs the differences in specific 
gravity of the rocks and minerals in the mill feed to achieve the separation of ore from waste material. 

high density sludge plant 

A waste water treatment plant wherein chemical additions (typically hydroxide or iron salts) are used to 
form a precipitate for the removal of heavy metals from solution, and where a portion of the sludge 
produced is returned to the beginning of the treatment process to provide adsorption nuclei. 

hydrophilic 

A substance that has an affinity for water. 

hydroxide 

A type of oxide characterized by the linkage of a metallic element or radical with the ion OH. 

in-situ leach 

Leaching of broken ore in the subsurface as it occurs, usually in abandoned underground mines which 

previously employed block-caving mining methods. 

INCO 

Acronym for the .International Nickel Company Limited. 

A.D - 6 APPENDIX D - GLOSSARY 



wp/3763-1 5/appendlxd. rep/a 

influent 

Waste water stream prior to treatment. 

iorvexchange 

An exchange of ions or in a crystal or resin with ions in solution in order to recover metals. 

jarosite 

A hydrated oxide of a heavy metal, most commonly Iron. 

leaching 

The extraction of soluble metals or salts from an ore by means of percolating solutions through ground 

ore. 



Quicklime (calcium oxide), obtained by calcining limestone or other forms of caelum carbonate. Loosely 
used for hydrated lime (calcium hydroxide) and incorrectly used for pulverized or ground calcium 
carbonate in agriculatural lime and for calcium in such expressions as carbonate of lime, chloride of 
lime, and lime feldspar. 

magnetic separation 

A process in which a magnetically susceptible mineral is separated from other materials by applying a 
strong magnetic field. 

magnetite 

Magnetic iron ore, being a black iron oxide containing 72.4% iron when pure. 

malachite 

A green, basic cupric carbonate, CU2(OH)2C03, crystallizing in the monoclinic system. It Is a common 
ore of copper and occurs typically in the oxidation zone of copper deposits. 

massive 

Any body of rock which is more or less homogeneous in texture or fabric, displaying an absence of flow 
layering, foliation, cleavage, joints or fissility. Has minor or no structural divisions. In the case of 
sulphide ores, the term refers to a large concentration of the ore In one place. 



APPENDIX D - GLOSSARY A.D - 7 



wp/3/63-15/appendlxd.rep/8 

Merrill-Crowe 

A gold recovery process in wliichi gold in cyanide solution is precipitated with zinc to produce a 
concentrate which Is subsequently refined to produce bullion. 

metallocyanide 

Complex Ions consisting of both cyanide and an associated heavy metal (e.g. Cu(CN)3^) 

mill 

1 ) A plant in which ore is treated for the recovery of valuable metals, or the concentration of valuable 

minerals into a smaller volume for shipment to a smelter or refinery. 

2) A piece of milling equipment consisting of a revolving drum, for the fine-grinding of ores as a 

preparation for treatment. 

f^lSA initial reports 

Documentation provided to MOE by Ontario mining operations, as part of the MISA monitoring program, 
outlining processes used for ore treatment, wastewater treatment facilities, and other operation details. 

MISA 

Acronym for the OMOE's Municipal and .Industrial Strategy for Abatement. 

native 

Any element that is found pure or uncombined in a nongaseous state in nature. 

natural degradation 

A process used to remove cyanide and metallocyanide complexes from ponded effluents, whereby 
cyanide is lost through volatilization to the atmosphere (where it subsequently degrades to carbon 
dioxide and ammonia) and conversion to cyanate and thiocyanate; and where heavy metals dissociated 
from metallocyanide complexes form precipitates. 



AD - 8 APPENDIX D - GLOSSARY 



vvp/3763-1S/appendlxd.rep/a 

non-lethal effluent 

An effluent which passes a toxicity test, generally using either fish or Daphnia, and most typically defined 
as an effluent In which at least 50 percent of the test organisms survive over 96 hours In 100% strength 
effluent (I.e. 96h LC 50). 

NSPS 

Acronym for New Jource Performance Standards used by the US EPA to define environemental 
performance criterial, where appliable, for effluent treatment plants commissioned subsequent to 1984. 

OMOE 

Acronym for the Ontario Ministry Of The Environment. 

oxidation 

The process of combining oxygen with elemental metals. 

passivation 

A chemical process which results in a reduced reactivity of a metal or element. 

pelletization 

The agglomeration of fine-grained particles, usually the magnetically separated material from ground iron 
ore, with the aid of a bonding agent. The pellets are dried and baked prior to shipment. 

pentiandite 

An iron and nickel sulphide mineral. 

plant 

A building or group of buildings, and their contained equipment, in which a process or function is carried 
out; at a mine it will incude warehouses, hoisting equipment, compressors, maintenance shops, offices, 
mill or concentrator. 

pollution abatement 

The process of reducing the concentration of contaminants to acceptabe levels in effluents. 



APPENDIX D - GLOSSARY A.D - 9 



wp/3763 ICi/uppendlxd.rep/a 

precipitation 

The combination of metals with other metals, hyroxides or sulphides to form larger solid particles in 
order to concentrate gold prior to refining or to remove heavy metals from wastewater. 

pressure oxidation 

A gold dissolution process used predominantly for refractory ores. The process involves the oxidation of 

gold bearing slurry under elevated oxygen pressure to liberate gold prior to carbon adsorption. 

pyrite 

A common sulphide mineral, shiny and yellow in colour and composed of sulphur and Iron, sometimes 

l<nown as "fool's gold" 

pyrometallurgical 

The nature of a process that employs heat to bring about a chemical change. 

radionuclides 

Those elements which have radioactive characteristics, such as uranium and radium. 

reactor/ciarifier 

A mechanical thickener with internal recycle of the sludge bed. 

reagent 

A chemical or solution used to produce a desired chemical reaction; a substance used in assaying or in 

flotation. 

recovery 

A general term to designate the valuable constituents of an ore which are obtained by metallurgical 

treatment. 

refining 

The process of purifying metals by pyrometallurgical or other methods. 



A.D - 10 APPENDIX D - GLOSSARY 



wp/3763-15/appendlxd.rep/a 

refractory gold 

Gold which is contained in ore which is bound with sulphides and is not amenable to cyanidatlon 
without oxidation (see pressure oxidation). 

regulation limit 

An effluent limit controlled by law. 

roasting 

The heating of an ore or concentrate in the presence of oxygen to remove sulphur and render the metal- 
sulpur In the concentrate more amenable to further processing. 

siderite 

Iron carbonate, which when pure, contains 48.2% Iron; must be roasted to drive off cartxsn dioxide 
before it can be used in a blast furnace. (Roasted product is called sinter) 

sintering 

The heating of finely ground ore, usually iron ore, in order to coalesce the ground ore into a larger 
particle. 

sludge 

The precipitant or settled material from a wastewater. 

smelting 

The process of extracting metal from ore by melting. 

sphalerite 

A sulphide mineral of zinc; a common ore mineral of zinc. 

sump 

An underground excavation where water accumulates before being pumped to surface. 

tailings voids 

pore spaces existing between solid phase tailings particles, which are occupied by either air or water. 



APPENDIX D - GLOSSARY A.D - 1 1 



wr)/1763-1 5/appendlxd.rep/a 

tailings pond 

A low-lying depression used to confine tailings, the prime function of which is to separate solids from 
liquids, store the solid material and where applicable to allow enough time for heavy metals to settle out 
or for cyanide to be destroyed before water is discharged into the receiving watershed. 

tailings 

That portion of ground and treated ore which contains insufficient quantities of a valuable material to be 

recovered by further processing and require subsequent disposal in some form of impoundment area. 

thickener 

A large, round tank used in milling operations to separate solids from liquids; clear flukl overflows from 

the tank and rock particles sink to the bottom. 

toxic contaminants 

A substance which can cause death, disease, behavioral abnormalties, cancer, genetic mutations, 
physiological or reproductive malfunctions, or physical deformities in any organism or its offspring, or 
which can become poisonous after concentration in the food chain or in combination with other 
substances. 

US EPA 

Acronym for the United States Environmental Protection Agency. 

virtual elimination of toxic contaminants 

The total elimination of toxic contaminants from an effluent attained through either zero volume 
discharge, or purification of an effluent to the point where 'not a molecule' of the contaminant remains. 

volatilization 

The decomposition and evaporation of chemical compounds. 



A.D - 12 APPENDIX D - GLOSSARY 



wp/3763- 1 5/Uibotcon.rep/a 



APPENDIX E 
CAPITAL AND OPERATING COST DETAILS FOR BAT 



TECHNOLOGY TRAIN; INCO S02-AIRn'AILINGS POND/POLISHING POND 
DESIGN CRITERIA UNITS 



INCO S02-Air 

No of operating days per year 

Solids in tailings 

Liquid in tailings 

Specific gravity of tailings slurry 

Flow rate of tailings slurry 

Plant availability 

Design flow rate of slurry 

No. of reactors 

Mean residence time per reactor 

CNT in feed slurry 

CNT in treated slurry 

Cyanide destroyed 

Consumption of S02* @ 5.5 g/g CNT 

Consumption of lime @ 1 .4 g/g S02 

Consumption of CuS04.5H20 @ 0.2 g/g CNT 

*The consumption of S02 could vary from 4 to 7 g/g CNT 

Tailings Pond 

Design life 

Mean final depth of tailings 

Dry bulk density of "in situ" tailings 

Void water in tailings 

Mean annual precipitation 

Mean annual evaporation 

Liquid pool area 

Total Watershed area 

Runoff coefficient 

Seepage loss (% of nett inflow) 

Polishing Pond 
Mean solution residence time 
Solution storage capacity 
Mean depth of solution 
Length of each side of pond 



# 


360 


360 


Vd 


750 


3000 


Vd 


1 125 


4500 


# 


1.346 


1.346 


m3/d 


1393 


5572 


% 


90 


90 


m3/h 


64.5 


258 


# 


1 


1 


min 


60 


60 


mg/L 


150 


150 


mg/L 


0.5 


0.5 


Va 


60.5 


242.2 


Va 


333 


1332 


Va 


466 


1865 


Va 


12.1 


48.4 



a 


5 


5 


m 


3 


5 


Vm3 


1.4 


1.4 


% 


26 


26 


mm 


780 


780 


mm 


500 


500 


ha 


9.6 


23 


ha 


83.2 


200 


# 


0.7 


0.7 


% 


5 


5 


d 


30 


30 


m3 


59 000 


180 000 


m 


2 


4 


m 


172 


212 



PAGE1 



TECHNOLOGY TRAIN; INCO S02-AIR/TA1LINGS POND/POUSHING PON D (continued) 
CAPITAL COSTS A 



INCO S02-Air 

Mechanical $353 000 $566 500 

Civil/structural 60% $212 000 $340 000 

Piping 25% $88 000 $142 000 

Electrical 20% $71000 $113 000 

Instrumentation 10% $35 000 $57 000 



DIRECT COST $759 000 $1 21 8 500 

Construction indirects 8% $61000 $97 000 

EPCM 15% $123 000 $197 000 

Contingency 10% $94 000 $151000 

INSTALLED COST (INCO S02-Alr) $1 037 000 $1 663 500 

INSTALLED COST (Polishing Pond) $209 000 $620 000 

INSTALLED COST (INCO S02-Air + Polishing Pond) $1 246 OOO $2 283 500 



OPERATING COSTS 



INCO S02-Air + Polishing Pond 
Annual cost of S02 @ $300A 
Annual cost of lime @ $140A 
Annual cost of CuS04.5H20 @ $1200A 



Annual cost of reagents 

Annual licence fee @ $0.33/l<g S02 

Annual cost of electricity (kW x SOOOh x $0.05/kWh) 

Annual cost of labour (2 persons @ $60 000) 

Annual cost of maintenance supplies 



$100 000 


$401000 


$65 000 


$262 000 


$14 500 


$58 500 


$179 500 


$721 500 


$110000 


$441000 


$40 000 


$80 000 


$120 000 


$120 000 


$21 000 


$34 000 



TOTAL ANNUAL OPERATING COST $470 500 $1 396 500 

UNIT OPERATING COST $/m3 $1.15 $0.86 

UNIT OPERATING COST $/t CN $7 760 $5 750 



PAGE 2 



TECHNOLOGY TRAIN: N.D./INCO S02-AIR/P0LISHING POND 
DESIGN CRITERIA UNITS 



INCO S02-Air 

No. of operating days per year 

Solution to be treated 

Plant availability 

Design flow rate of solution 

No. of reactors 

Mean residence time per reactor 

ONT in feed slurry 

ONT in treated slurry 

Cyanide destroyed 

Consumption of S02* @ 4.0 g/g CNT 

Consumption of lime @ 1.7 g/g S02 

Consumption of CuS04.5H20 @ 0.2 g/g CNT 

*The consumption of S02 could vary from 3 to 5 g/g CNT 

Polishing Pond 
Mean solution residence time 
Solution storage capacity 
Mean depth of solution 
Length of each side of pond 

CAPITAL COSTS 



# 


180 


180 


m3 


707 000 


2 161 000 


% 


90 


90 


m3/h 


182 


556 


# 


1 


1 


min 


40 


40 


mg/L 


25 


25 


mg/L 


0.5 


0.5 


Va 


17.3 


52.9 


l/a 


69.3 


212 


t/a 


117.8 


360 


t/a 


3.5 


10.6 



d 


30 


30 


m3 


131 000 


400 000 


m 


2 


4 


m 


256 


316 



INCO S02-Air 

Mechanical 

Civil/structural 

Piping 

Electrical 

Instrumentation 



$323 000 $472 000 

60% $194 000 $283 000 

25% $81000 $118 000 

20% $65 000 $94 000 

10% $32 000 $47 000 



DIRECT COST 
Construction indirects 
EPCM 
Contingency 



INSTALLED COST (INCO S02-Air) 
INSTALLED COST (Polishing Pond) 
INSTALLED COST (INCO S02-Air + Polishing Pond) 



$695 000 $1 014 000 

8% $56 000 $81 000 

15% $113 000 $164 000 

10% $86 000 $126 000 



$950 000 $1 385 000 

$31 1 000 $924 000 

$1 261 000 $2 309 000 



TABLES 



TECHNOLOGY TRAIN: N.D./INCO S02-AIR/POLISHING POND (continued) 

OPERATING COSTS A B 

INCO S02-Air + Polishing Pond 

Annual cost of S02 @ $300A $21 000 $63 500 

Annual cost of lime @ $1 40A $1 6 500 $50 500 

Annual cost of CuSO4.5H2O@$1200/t $4 000 $13 000 

Annual cost of reagents 

Annual licence fee @ $0.33/kg S02 

Annual cost of electricity (kW x 4000h x $0.05/kWh) 

Annual cost of labour (2 persons @ $30 000) 

Annual cost of maintenance supplies 

TOTAL ANNUAL OPERATING COST 
UNIT OPERATING COST 
UNIT OPERATING COST 





$41500 


$127 000 




$23 000 


$70 000 




$10 000 


$15500 




$60 000 


$60 000 




$9 500 


$14 000 




$144 000 


$286 500 


$/m3 


$0.20 


$0.13 


$ACN 


$8 320 


$5 420 



TABLES PAGE 4 



TECHNOLOGY TRAIN: N.D /HYDROGEN PEROXIDE/POUSHING POND 
DESIGN CRITERIA UNITS 



Hydrogen Peroxide 

No. of operating days per year 

Solution to be treated 

Plant availability 

Design flow rate of solution 

No. of reactors in series 

Mean residence time per reactor 

CNT in feed sluny 

CNT in treated slurry 

Cyanide destroyed 

Consumption of H202* @ 6.0 g/g CNT 

Consumption of lime @ 0.35 kg/m3 

Consumption of CuS04.5H20 @ 0.2 g/g ONT 

*The consumption of H202 could vary from 4 to 10 g/g CNT 



# 


180 


180 


m3 


707 000 


2161000 


% 


90 


90 


m3/h 


182 


556 


# 


2 


2 


min 


20 


20 


mg/L 


25 


25 


mg/L 


0.5 


0.5 


t/a 


17.3 


52.9 


t/a 


104 


317 


Va 


247 


756 


Va 


3.5 


10.6 



Polishing Pond 
Mean solution residence time 
Solution storage capacity 
Mean depth of solution 
Length of each side of pond 

CAPITAL COSTS 



Hydrogen Peroxide 

Mechanical 

Civil/stmctural 

Piping 

Electrical 

Instrumentation 



DIRECT COST 
Construction indirects 
EPCM 
Contingency 



d 


30 


30 


m3 


131 000 


400 000 


m 


2 


4 


m 


256 


316 



$332 000 $475 000 

60% $199 000 $285 000 

25% $83 000 $119 000 

20% $66 000 $95 000 

10% $33 000 $48 000 



$713 000 $1022 000 

8% $57 000 $82 000 

15% $116 000 $166 000 

10% $89 000 $127 000 



INSTALLED COST (Hydrogen Peroxide) 

INSTALLED COST (Polishing Pond) 

INSTALLED COST (Hydrogen Peroxide + Polishing Pond) 



$975 000 $1 397 000 

$31 1 000 $924 000 

$1 286 000 $2 321 000 



TECHNOLOGY TRAIN: N.D./HYDROGEN PEROXIDE/POUSHING POND (continued) 
OPERATING COSTS A 



Hydrogen Peroxide + Polishing Pond 

Annual cost of H202 @ $1 800/t $1 87 000 $570 500 

Annual cost of lime @ $140A $34 500 $106 000 

Annual cost of CuS04. 5H20 @ $1 200A $4 000 $1 3 000 



Annual cost of reagents $225 500 $689 500 

Annual cost of electricity (kW x 4000h x $0.05/kWh) $7 500 $1 1 500 

Annual cost of labour (2 persons @ $30 000) $60 000 $60 000 

Annual cost of nnaintenance supplies $10 000 $14 500 

TOTAL ANNUAL OPERATING COST $303 000 $775 500 

UNIT OPERATING COST $/m3 $0.43 $0.36 

UNIT OPERATING COST $A CN $17 510 $14 660 



APPENDIX E TABLES 



TECHNOLOGY TRAIN: N.D /INCO S02-AIR/CLARIFICATI0N 

DESIGN CRITERIA 

INCO S02-Air 

No of operating days per year 

Solution to be treated 

Plant availability 

Design flow rate of solution 

No. of reactors 

Mean residence time per reactor 

CNT in feed slurry 

CNT in treated slurry 

Cyanide destroyed 

Consumption of 802* @ 4.0 g/g CNT 

Consumption of lime @ 1 .7 g/g S02 

Consumption of CuS04.5H20 @ 0.2 g/g CNT 

*The consumption of S02 could vary from 3 to 5 g/g CNT 

Clarification 

Design flow rate of feed 
Specific clarification area 
Diameter of clarifier 
Flocculant addition 
Consumption of flocculant 

CAPITAL COSTS 

INCO S02-Air + Clarification 

Mechanical 

Civil/structural 

Piping 

Electrical 

Instrumentation 



UNITS 



# 


180 


180 


m3 


707 000 


2 161000 


% 


90 


90 


m3/h 


182 


556 


# 


1 


1 


min 


40 


40 


mg/L 


25 


25 


mg/L 


0.5 


0.5 


t/a 


17.3 


52.9 


Va 


69.3 


212 


Va 


117.8 


360 


Va 


3.5 


10.6 



m3/h 


182 


556 


m2/m3/h 


2.5 


2.5 


m 


24 


42 


g/m3 


10 


10 


Va 


7.1 


21.6 




A 


B 



$654 000 $955 000 

60% $392 000 $573 000 

25% $164 000 $239 000 

20% $131 000 $191 000 

10% $65 000 $96 000 



DIRECT COST 
Construction indirects 
EPCM 
Contingency 



INSTALLED COST (INCO S02-Air + Clarification) 



$1 406 000 $2 054 000 

8% $112 000 $164 000 

15% $228 000 $333 000 

10% $175 000 $255 000 



$1 921 000 $2 806 000 



TABLES 



PAGE 7 



TECHNOLOGY TRAIN: N.D./INCO S02-AIR/CLARIFICAT10N (continued) 

OPERATING COSTS 

INCO S02-Air + Clarification 
Annual cost of S02 @ $300A 
Annual cost of lime @ $140/t 
Annual cost of CuS04.5H20 @ $1200/t 
Annual cost of flocculant @ $3000A 



Annual cost of reagents 

Annual licence fee @ $0.33/kg S02 

Annual cost of electricity (kW x 4000h x $0.05/kWh) 

Annual cost of labour (2 persons @ $30,000/a) 

Annual cost of maintenance supplies 



$21CX)0 


$63 500 


$16500 


$50 500 


$4 000 


$13 000 


$21 500 


$65 000 


$63 000 


$192 000 


$23 000 


$70 000 


$11 500 


$16000 


$60 000 


$60 000 


$19 500 


$28 500 



TOTAL ANNUAL OPERATING COST $1 77 000 $368 500 

UNIT OPERATING COST $/nr»3 $0.25 $0.17 

UNIT OPERATING COST $/tCN $10 230 $6 970 



PAGE I 



TECHNOLOGY TRAIN: N.D./HYDROGEN PEROXIDE/CLARIFICATION 
DESIGN CRITERIA UNITS 



Hydrogen Peroxide 

No. of operating days per year 

Solution to be treated 

Plant availability 

Design flow rate of solution 

No. of reactors in series 

Mean residence time per reactor 

CNT in feed slurry 

ONT in treated slurry 

Cyanide destroyed 

Consumption of H202 @ 6.0 g/g CNT 

Consumption of lime @ 0.35 kg/m3 

Consumption of CuS04.5H20 @ 0.2 g/g CNT 

Clarification 

Design flow rate of feed 
Specific clarification area 
Diameter of clarifler 
Floccuiant addition 
Consumption of floccuiant 



# 

m3 

% 

m3/h 

# 

min 

mg/L 

mg/L 

Va 

Va 

Va 

Va 



m3/h 

nr\2/m3/h 

m 

g/m3 

Va 



180 

707 000 

90 

182 

2 

20 

25 

0.5 

17.3 

104 

247 

3.5 



182 
2.5 
24 
10 
7.1 



2161 000 

90 

556 

2 

20 

25 

0.5 

52.9 

317 

756 

10.6 



556 
2.5 
42 
10 

21.6 



CAPITAL COSTS 



Hydrogen Peroxide + Clariflcation 








Mdchânic&i 




$662 000 


$996 000 


Civil/structural 


60% 


$397 000 


$598 000 


Piping 


25% 


$166 000 


$249 000 


Electrical 


20% 


$132 000 


$199 000 


Instrumentation 


10% 


$66 000 


$100 000 


DIRECT COST 




$1 423 000 


$2 142 000 


Construction indirects 


8% 


$114 000 


$171000 


EPCM 


15% 


$231000 


$347 000 


Contingency 


10% 


$177 000 


$266 000 


INSTALLED COST 




$1 945 000 


$2 926 000 



APPENDIX E 



PAGE 9 



TECHNOLOGY TRAIN: N.D./HYDROGEN PEROXIDE/CLARIFICATION (continued) 

OPERATING COSTS A B 

Hydrogen Peroxide + Clarification 

Annual cost of H2O2@$1800/t $187 000 $570 500 

Annual cost of lime @ $1 40A $34 500 $1 06 000 

Annual cost of CuS04.5H20 @ $1200A $4 000 $13 000 

Annual cost of flocculant @ $3000A $21 500 $65 000 



Annual cost of reagents $247 000 $754 500 

Annual cost of electricity (kW x 4000h x $0.05/kWh) $9 000 $1 4 000 

Annual cost of labour (2 persons @ $30 000) $60 000 $60 000 

Annual cost of maintenance supplies $20 000 $30 000 

TOTAL ANNUAL OPERATING COST $336 000 $858 500 

UNIT OPERATING COST $/m3 $0.48 $0.40 

UNIT OPERATING COST $A CN $19 420 $16 230 



APPENDIX E TABLES PAGE 10 



TECHNOLOGY: FERRIC COPRECIPITATION 



DESIGN CRITERIA 



No. of operating days per year 

Design flow rate of solution (m3/h) 

Plant availability 

No. of reactors in series 

Mean residence time per reactor 

As in feed solution 

As in treated solution 

Design Fe/As molar ratio 

As removed 

Consumption of Fe2(S04)3 @ 2.1 tA As 

Consumption of lime @ 0.8 kg/kg Fe2 (S04)3 



# 


180 


180 


rn3l\n 


182 


556 


% 


90 


90 


# 


2 


2 


min 


15 


15 


mg/L 


5 


5 


mg/L 


0.2 


0.2 


# 


10:1 


10:1 


t/a 


3.4 


10.4 


t/a 


7.1 


21.6 


Va 


5.7 


17.3 



CAPITAL COSTS 



Mechanical 

Civil/structural 

Piping 

Electrical 

Instrumentation 



$186 000 $256 000 

60% $112 000 $154 000 

25% $47 000 $64 000 

20% $37 000 $51 000 

10% $19 000 $26 000 



DIRECT COST 
Construction indirects 
EPCM 
Contingency 



$401 000 $551 000 

8% $32 000 $44 000 

15% $65 000 $89 000 

10% $50 000 $68 000 



INSTALLED COST 



$548 000 $752 000 



PAGE 11 



TECHNOLOGY: FERRIC COPRECIPITATION (continued) 
OPERATING COSTS 



Annual cost of Fe2 (S04)3 @ $600/t $4 500 $1 3 000 

Annual cost of lime @ $140A $1 000 $2 500 

Annual cost of reagents $5 500 $1 5 500 

Annual cost of electricity (kW x 4000h x $0.05/kWh) $3 500 $6 500 

Annual cost of maintenance supplies $6 000 $8 500 

TOTAL ANNUAL OPERATING COST $1 5 000 $30 500 

UNIT OPERATING COST $/m3 $0.02 $0.01 



PAGE 12 



TECHNOLOGY TRAIN: N.D./HEMLO PROCESS/CLARIFICATION 
DESIGN CRITERIA UNITS 



Hemlo Process 

No, of operating days per year 

Solution to be treated 

Plant availability 

Flow rate of solution 

No. of primary reactors in series 

Mean residence time per reactor 

CNT in feed solution 

CNT in treated solution 

Cyanide destroyed 

Consumption of CuSC)4.5H20 @ 12 g/g CNT 

Consumption of FeS04 @ 23 g/g CNT 

Consumption of Fe2(S04)3 @ 1 g/g CNT 

Consumption of lime @ 1 g/g CNT 

Clarification 
Design feed flow rate 
Specific clarification area 
Diameter of clarifier 
Flocculant addition 
Consumption of flocculant 

CAPITAL COSTS 

Hemlo Process + Clarification 

Mechanical 

Civil/structural 

Piping 

Electrical 

Instrumentation 



# 


180 


180 


rtiS/a 


707 000 


2161000 


% 


90 


90 


nr»3/h 


182 


556 


# 


3 


3 


min 


15 


15 


mg/L 


6 


6 


mg/L 


0.5 


0.5 


t/a 


3.9 


11.9 


Va 


46.7 


142.6 


t/a 


89.4 


273 


Va 


3.9 


11.9 


Va 


38.9 


118.9 


m3/h 


182 


556 


m2/m3/h 


2.5 


Z5 


m 


24 


42 


g/m3 


10 


10 


Va 


7.1 


21.6 




A 


B 



$923 000 $1 385 000 

60% $554 000 $831 000 

25% $231 000 $346 000 

20% $185 000 $277 000 

10% $92 000 $139 000 



DIRECT COST 
Construction indirects 
EPCM 
Contingency 



$1 985 000 $2 978 000 

8% $159 000 $238 000 

15% $322 000 $482 000 

10% $247 000 $370 000 



INSTALLED COST (Hemlo Process + Clarification) 



$2 713 000 $4 068 000 



PAGE 13 



TECHNOLOGY TRAIN: N.D./HEMLO PROCESS/CLARIFICATION (continued) 
OPERATING COSTS 



Hemlo Process + Clarification 
Annual cost of CuS04.5H20 @ $1200A 
Annual cost of FeS04 @ $400/t 
Consumption of Fe2(S04)3 @ 1 g/g CNT 
Annual cost of lime @ $140A 
Annual cost of flocculant @ $3000/t 



Annual cost of reagents 

Annual cost of electricity (kW x 4000h x $0.05/kWh) 
Annual cost of labour (2 persons @ $30 000) 
Annual cost of maintenance supplies 

TOTAL ANNUAL OPERATING COST 
UNIT OPERATING COST 
UNIT OPERATING COST 





$56 000 


$171000 




$36 000 


$109 000 




$2 500 


$7 000 




$5 500 


$16 500 




$21500 


$65 000 




$121500 


$368 500 




$29 500 


$66 000 




$60 000 


$60 000 




$27 500 


$41500 


= = = = 


======= 






$238 500 


$536 000 


$/m3 


$0.34 


$0.25 


$ACN 


$61 150 


$45 040 



Note: This estimate was made in the absence of published reagent consumptions. 



APPENDIX E TABLES 



7.2 BASE METAL SECTOR 

TECHNOLOGY TRAIN: TAILINGS POND/HYDROXIDE PRECIPITATION/POLISHING POND 

DESIGN CRITERIA UNITS A 



Hydroxide Precipitation 

No. of operating days per year 

Design flow rate of solution 

Plant availability 

Solution treated 

No. of reactors in series 

Mean residence time per reactor 

Rate of addition of lime 

Consumption of lime 

Polishing Pond 
Mean solution residence time 
Solution storage capacity 
Mean depth of solution 
Length of each side of pond 



# 


360 


360 


m3/h 


75 


300 


% 


90 


90 


m3/a 


583000 


2333 000 


# 


2 


2 


min 


15 


15 


kg/m3 


0.2 


0.2 


t/a 


117 


467 


d 


30 


30 


m3 


48 500 


194 500 


m 


2 


4 


m 


156 


221 



CAPITAL COSTS 



Hydroxide Precipitation 

Mechanical 

Civil/structural 

Piping 

Electrical 

Instrumentation 



DIRECT COST 
Construction indirects 
EPCM 
Contingency 



INSTALLED COST (Hydroxide Precipitation) 

INSTALLED COST (Polishing Pond) 

INSTALLED COST (Hydroxide Precipitation + Polishing Pond) 





$151000 


$289 500 


60% 


$91000 


$174 000 


25% 


$38 000 


$72 000 


20% 


$30 000 


$58 000 


10% 


$15000 


$29 000 



$325 000 $622 500 

8% $26 000 $50 000 

15% $53 000 $101000 

10% $40 000 $77 000 



$444 000 $850 500 
$189 500 $646 500 
$633 500 $1 497 000 



OPERATING COSTS 



Hydroxide Preciprtation + Polishing Pond 

Annual cost of lime @ $140/t 

Annual cost of electricity 

Annual cost of labour (2 persons @ $60 000) 

Annual cost of maintenance supplies 



TOTAL ANNUAL OPERATING COST 
UNIT OPERATING COST 



$16 500 


$65 500 


$16 000 


$30 000 


5120 000 


$120 000 


$9 000 


$17 500 



$/m3 



$161 500 
$0.28 



$233 000 
$0.10 



TECHNOLOGY TRAIN, MINE WATER POND/HYDROXIDE PRECIPITATION/CLARIFICATION 
DESIGN CRITERIA UNITS A 



Hydroxide Preciprtation 

Design flow rate of solution 

No. of operating days per year 

Plant availability 

Solution treated 

No. of reactors in series 

Mean residence time per reactor 

Rate of addition of lime 

Consumption of lime 

Clarification 

Specific clarification area 
Rate of addition of flocculant 
Consumption of flocculant 



CAPITAL COSTS 



m3/h 


75 


300 


# 


360 


360 


% 


90 


90 


m3/a 


583 000 


2333 000 


# 


2 


2 


min 


30 


30 


kg/m3 


2 


2 


Va 


1166 


4666 


m2/rr<3/h 


2.5 


2.5 


g/m3 


5 


5 


t/a 


2.9 


11.7 




A 


B 



Hydroxide Precipitation + Clarification 

Mechanical 

Civil/structural 

Piping 

Electrical 

Instrumentation 



$666 000 $1 246 500 

60% $400 000 $748 000 

25% $167 000 $312 000 

20% $133 000 $249 000 

10% $67 000 $125 000 



DIRECT COST 
Construction indirects 
EPCM 
Contingency 



$1 433 000 $2 680 500 

8% $115 000 $214 000 

15% $232 000 $434 000 

10% $178 000 $333 000 



INSTALLED COST (Hydroxide Precip. + Clarification) 


$1 958 000 


$3 661500 


OPERATING COSTS 


A 


B 


Hydroxide Precipitation + Clarification 
Annual cost of lime @ $1 40/t 
Annual cost of flocculant @ $3000/t 


$163 000 
$8 500 


$653 000 
$35 000 



Annual cost of reagents 

Annual cost of electricity (kW x 8000h x $0.05/kWh) 
Annual cost of labour (2 persons @ $60 000) 
Annual cost of maintenance supplies 



$171500 $688 000 

$28 000 $72 000 

$120 000 $120 000 

$40 000 $75 000 



TOTAL ANNUAL OPERATING COST 
UNIT OPERATING COST 



$/m3 



$359 500 
$0.62 



$955 000 
$0.41 



TABLES 



TECHNOLOGY TRAIN: TAIUNGS POND/SULPHIDE PRECIPITATION/CLARIFICATION 



DESIGN CRITERIA 



Sulphide Precipitation 

Design flow role of solution 

No of operating days per year 

Plarrt availability 

Solution treated 

No of reactors in series 

Mean residence time per reactor 

Concerrtrate of dissolved metals 

Rate of addition of Na2S 

Consumption of Na2S 

Clarification 

Effective plate area in Lamella clarifier 

Rate of addition of flocculant 

Consumption of flocculant 

No. of Dynasand filters in parallel 

Cross-sectional area per filter 

Rate of addition of flocculant 

Consumption of flocculant 



n-^S/h 


75 


300 


# 


360 


360 


% 


90 


90 


m3/a 


583 000 


2333 000 


# 


2 


2 


mirw 


15 


15 


mg Cu equiv/L 


5 


5 


g/g Cu equiv 


1.2 


1.2 


t/a 


3.5 


14 


m2 


64 


290 


g/m3 


2 


2 


t/a 


1.2 


4.7 


# 


1 


4 


m2 


5.9 


5.9 


g/m3 


1 


1 


Va 


0.6 


2.3 



CAPITAL COSTS 



Sulphide Precipitation + Clarification 

Mechanical 

Civil/structural 

Piping 

Electrical 

Instrumentation 



DIRECT COST 
Construction indirects 
EPCM 
Contingency 



$526 000 $1123 000 

60% $316 000 $674 000 

25% $132 000 $281000 

20% $105 000 $225 000 

10% $53 000 $112 000 

$1132 000 $2 415 000 

8% $91000 $193 000 

15% $183 000 $391000 

10% $141000 $300 000 



INSTALLED COST (Sulphide Precip. + Clarification) 



$1 547 000 $3 299 000 



OPERATING COSTS 



Sulphide Precipitation + Clarification 

Annual cost of Na2S @ $1400A 

Annual cost of flocculant @ $3000A 

Annual cost of electricity 

Annual cost of labour (2 persons @ $60 000) 

Annual cost of maintenance supplies 



$5 000 


$19 500 


$5 500 


$21000 


$22 000 


$40 000 


$120 000 


$120 000 


$31500 


$67 500 


$184 000 


$268 000 


$0.32 


$0.11 



TOTAL ANNUAL OPERATING COST 
UNIT OPERATING COST 



$/m3 



APPENDIX E 



TABLES 



PAGE 17 



wp/'J763 15/Ubotcon.rep/B 



APPENDIX F 
CAPITAL AND OPERATING COSTS FOR ZERO VOLUME DISCHARGE 



wp/3763- 1 S/appendlirt.rep/a 

ONTARIO MINISTRY OF THE ENVIRONMENT 

METAL MINING SECTOR 

BEST AVAILABLE POLLUTION CONTROL TECHNOLOGY 

APPENDIX F - CAPITAL AND OPERATING COSTS FOR ZERO VOLUME DISCHARGE 

Zero volume discharge could only be achieved in Ontario through forced evaporation of the net liquid 

effluent. 

The design criteria and 'order of magnitude' capital and operating costs to evaporate 1 000 and 4 000 
r?/day of liquid effluent to dryness are presented below. The costs are based on the use of natural gas 
fired, single effect evaporators followed by flash drying to produce a dry solid residue for disposal. 



Design Criteria 

No. of operating days per year 

Design flow rate of solution 

Plant availability 

Total water vapourized 

Water vapourized in evaporator 

Water vapourized in flash dryer 

Efficiency of vapourization process 

Capital and Operating Costs 
Installed cost 
Annual operating cost 
Unit operating cost 



Note : 

(1 ) The capital costs are based on the use of carbon steel as the material of construction for the 
evaporators and flash dryer. 

(2) The unit cost of natural gas is $129/million rr?. 

(3) Natural gas accounts for over 90% of the total operating cost. 

CAPITAL AND OPERATING COSTS FOR ZERO VOLUME DISCHARGE A.F - 1 



Units 


Case A 


Cases 


# 


360 


360 


nrr'/d 


1 000 


4 000 


% 


90 


90 


m'/a 


3 24 000 


1 296 000 


rr^/a 


307 800 


1 231 200 


m'/a 


16 200 


64 800 


% 


75 


75 



$ 


2 200 000 


5 000 000 


$ 


45 00 000 


16 500 000 


^ 


13.89 


12.50 



wp/3763- 1 5/appendlxt.rep/a 

(4) No allowance was made for the cost of feed pretreatment (e.g. pH adjustment and deaeration), if 
required. 

(5) Costs are expressed in fourth quarter 1 991 . Canadian dollars. 



A F • 2 CAPITAL AND OPERATING COSTS FOR ZERO VOLUME DISCHARGE